UNIVERSIDADE ESTADUAL DE CAMPINAS FACULDADE DE ENGENHARIA DE ALIMENTOS
AMANDA DE CÁSSIA NOGUEIRA
Enriquecimento proteico de biscoitos: utilização de diferentes hidrolisados e isolados proteicos
Protein enrichment of biscuits: use of different protein hydrolysates and isolates
CAMPINAS 2019
AMANDA DE CÁSSIA NOGUEIRA
Enriquecimento proteico de biscoitos: utilização de diferentes hidrolisados e isolados proteicos
Protein enrichment of biscuits: use of different protein hydrolysates and isolates
Tese apresentada à Faculdade de Engenharia de Alimentos da Universidade Estadual de Campinas como parte dos requisitos exigidos para a obtenção do título de Doutora em Tecnologia de Alimentos Thesis presented to the Faculty of Food Engineering of the University of Campinas in partial fulfillment of the requirements for the degree of Doctor in Food Technology
Supervisor/Orientador: Caroline Joy Steel ESTE EXEMPLAR CORRESPONDE À VERSÃO FINAL DA TESE DEFENDIDA PELA ALUNA AMANDA DE CÁSSIA NOGUEIRA, E ORIENTADA PELA PROFA. DRA. CAROLINE JOY STEEL
CAMPINAS 2019
BANCA EXAMINADORA
Profa. Dra. Caroline Joy Steel
Faculdade de Engenharia de Alimentos – UNICAMP (Membro titular)
Profa. Dra. Cinthia Bau Betim Cazarin
Faculdade de Engenharia de Alimentos – UNICAMP (Membro titular)
Profa. Dra. Eveline Lopes Almeida
Universidade Federal do Rio de Janeiro – UFRJ (Membro titular)
Profa. Dra. Flavia Maria Netto
Faculdade de Engenharia de Alimentos – UNICAMP (Membro titular)
Prof. Dr. Marcio Schmiele
Universidade Federal dos Vales do Jequitinhonha e Mucuri – UFVJM
(Membro titular)
A ata da defesa com as respectivas assinaturas dos membros encontra-se no SIGA/Sistema de Fluxo de Dissertação/Tese e na Secretaria do Programa da Unidade.
Pai, por tudo que vivemos, obrigada; por tudo que viveremos, sim! Ivna Sá
DEDICATÓRIA
Àquele que se foi e àquele que chegou durante este tempo: meu Pai e meu Filho, eu dedico!
AGRADECIMENTOS
Pensar em quantas pessoas estiveram comigo durante este tempo, que permaneceram ou passaram pela minha vida. Deixaram marcas especiais e a gratidão é imensa! Mensurar em palavras será difícil, mas vou tentar...
Agradeço:
Imensamente à Deus: pelo dom da vida, pela oportunidade de chegar até aqui; pelo Seu amor e misericórdia sem fim; por ter me carregado no colo, me fortalecido e me capacitado. Meu louvor é eterno!
À minha família, meu porto seguro!!! Sem eles, nada disso seria possível. *Ao meu esposo Alex, parceiro de vida e de sonhos. Por me incentivar sempre, acreditando em mim em todos os momentos! Obrigada pela família que nos tornamos! Te amo!
*À minha mãe Vera, exemplo de mulher forte! Pelo amor, cuidado, ajuda, incentivo, colo amoroso que só uma mãe é capaz de dar! Te amo e te admiro!
*Aos meus irmãos Bruno e Lavínia, pelo carinho, ajuda, parceria! Amo vocês! *Ao meu pai José Cláudio, meu herói, meu incentivador de voos altos, minha calmaria... que falta faz! Mas sei que do ladinho de Deus comemora comigo esta conquista! Saudades! Te amo!
*Ao meu filho Filipe! Obrigada por mostrar a mamãe que existe um amor tão grande! Obrigada pelo desejo que coloca em meu coração de ser uma pessoa melhor a cada dia! Obrigada por ter vindo durante este tempo!
*À minha segunda família: Maria Helena, Alessandro, Thais e minha afilhadinha Helena!
*Aos meus tios, tias, primos e primas, pelo carinho e torcida!
À professora Caroline, pela orientação, amizade e contribuições! Por toda compreensão durante este período, pela sua humanidade! Pela oportunidade de ter aprendido tanto, pelas conversas, confiança e incentivo! Minha sincera gratidão!
Agradeço também aos professores da área de Cereais: professora Dra. Maria Teresa e Professor Dr. Yoon, pela confiança, aprendizado e incentivo!
Aos técnicos e funcionários do DTA: Izilda, Bete, Juliana, Leila, Sandra, Seu Nilo, por toda ajuda e amizade!
Ao querido LabCer e agregados! Pelo carinho, acolhimento, ajuda, conversas e cafés! Amizades para a vida!! Por todas as pessoas que por ali passaram e lá
ainda estão, tenho imensa gratidão. Gostaria de expressar o meu muito obrigada ao Marcio, Georgia, Lud, Lara, Fernanda, Mária, Thaísa, Amanda Rios, Elisa, Ulliana, Aline, Flávio, Zé, Luis, Izilda, Michele, Ana, Carla, Gisela, Rebeca, Jeferson, Ana Paula Rebellato, Ana Paula Carvalho, Wellington e Alexandre.
À Renata, Rodrigo e Rafael, por toda ajuda no desenvolvimento do projeto. Obrigada pela dedicação e companhia ao longo de muitas análises...
Às amigas de república, pela companhia, amizade, cafés, jantas e saídas! Pelo apoio e preocupação! Obrigada Mírian, Grazi, Melissa, Ju, Gi!
Aos amigos de Poços pela torcida! Aos amigos do JUCA e RCC, pela oração! Agradeço à Fundação Agrária de Pesquisa Agropecuária – FAPA, Cooperativa Agrária Agroindustrial, pela parceira na realização da análise de SRC®,
de maneira especial à pessoa do Juliano.
À Bunge e à NovaProm pela doação da farinha de trigo e do hidrolisado proteico de colágeno, respectivamente.
Agradeço à professora Dra. Vanessa Capriles e Etiene pela ajuda e parceria na análise de MixolabTM.
Gostaria de agradecer à banca avaliadora (membros titulares e suplentes), professores Dra. Cinthia Bau Betim, Dra. Eveline Lopes Almeida, Dra. Flavia Maria Netto, Dr. Marcio Schmiele, Dra. Elizabeth Harumi Nabeshima, Dra. Maria Teresa Bertoldo Pacheco e Dra. Solange Guidolin Canniati Brazaca por todos os comentários e observações pertinentes que só acrescentaram ao trabalho e ao meu crescimento profissional.
O presente trabalho foi realizado com o apoio da Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brasil (CAPES) – Código de Financiamento 001.
Agradecemos também ao CNPq (Processos 140530/2015-0 e
307839/2016-8) e à FAPESP (Processo 2017/04519-1) pelo apoio financeiro. À UNICAMP, e em especial ao Departamento de Tecnologia de Alimentos/FEA e seus funcionários, por permitirem a realização desta pesquisa, e por me acolherem tão bem. Obrigada a todos os professores do DTA, pela disponibilidade e atenção de sempre, e à secretária Cláudia por estar sempre pronta a nos socorrer, pela atenção, disponibilidade e gentileza de sempre.
9 RESUMO
Na busca por atender aos consumidores que procuram por produtos que forneçam mais que a nutrição básica, os biscoitos tornam-se potenciais veículos de enriquecimento, tanto pelo seu amplo consumo, quanto pelo seu crescente mercado, principalmente do segmento de biscoitos saudáveis. Na mesma tendência, produtos enriquecidos com proteínas têm encontrado espaço, uma vez que, além de propiciarem maior teor proteico e de aminoácidos essenciais, podem fornecer saciedade. Assim, enriquecer biscoitos com proteínas não só melhora o aporte proteico, como compensa a deficiência em certos aminoácidos limitantes da farinha de trigo, principal ingrediente destes produtos. Para o enriquecimento de biscoitos, a utilização de hidrolisados e isolados proteicos pode ser viável. A utilização de hidrolisados proteicos é uma alternativa ainda muito pouco explorada. Hidrolisados proteicos de soro de leite e de colágeno são potenciais fontes para este fim, pela sua composição em aminoácidos e também pela possibilidade do uso combinado dos mesmos. Já os isolados proteicos, de proteínas de leguminosas, como soja e ervilha, e também de soro de leite, podem ser utilizados devido ao apelo nutricional e funcional que apresentam. Estas fontes proteicas, embora bastante estudadas quanto às suas características funcionais, têm sua funcionalidade dependente do meio no qual estão inseridos. Dessa forma, o objetivo deste estudo foi desenvolver biscoitos com alto teor de proteínas, e boa qualidade e disponibilidade proteicas, correlacionando as fontes de proteínas utilizadas com as características reológicas, de processo, tecnológicas, sensoriais e nutricionais: primeiramente em biscoitos tipo cookies, utilizando-se os hidrolisados proteicos de soro de leite (HC) e de colágeno (HS) e; posteriormente em biscoitos moldados doces, usando os isolados proteicos de ervilha (IPE), soja (IPS) e soro de leite (IPSL). Os hidrolisados e isolados enfraqueceram as massas de farinha de trigo (FT), limitando as substituições em 5 e 10%, respectivamente, para a manutenção das características viscoelásticas da massa. Todavia, para a produção de biscoitos, substituições maiores se mostraram adequadas. O teor de água a ser adicionado nas massas foi aumentado pelos isolados e diminuído pelos hidrolisados, modificando também o tempo de forno. As características
10 tecnológicas foram alteradas, como aumento da umidade e atividade de água, além do escurecimento dos biscoitos. As dimensões também foram afetadas: hidrolisados aumentaram o diâmetro e os isolados diminuíram a espessura e aumentaram o fator de expansão. Mesmo com as modificações, os biscoitos foram bem aceitos, apresentando notas para aparência e cor iguais ou melhores que o controle. Todavia, o gostoamargo foi detectado, principalmente com a adição dos hidrolisados, diminuindo, assim, a intenção de compra. Apesar disso, foram produzidos biscoitos de qualidade desejável e que alcançaram maior teor e qualidade proteica, assim como altos valores de digestibilidade. A adição de 10% HS/10% HC permitiu dobrar o conteúdo de proteína e aminoácidos, com aumento de 66% no conteúdo de lisina. Já os ensaios com 6% IPE/24% IPS/6% IPSL e com 15% IPE/15% IPS/15% IPSL, puderam ser considerados “alimento fonte de proteína”, com seus teores proteicos e de lisina aumentados em 68 e 70%, e em 56 e 62%, respectivamente.
11 ABSTRACT
In an effort to attend consumers looking for products that provide more than basic nutrition, cookies are potential enrichment vehicles, both for their wide-spread consumption, and for their growing market, especially of the segment of healthy biscuits. In the same trend, protein enriched products have found space, since, in addition to providing higher protein and essential amino acids contents, they can provide satiety. Thus, enriching biscuits with proteins not only improves the protein supply, but also compensates for the deficiency in certain limiting amino acids of wheat flour, the main ingredient of these products. For the enrichment of cookies, the use of protein hydrolysates and protein isolates may be feasible. The use of protein hydrolysates is an alternative still very little explored. Protein hydrolysates of whey and collagen are potential sources for this purpose, due to the diversity of the amino acids that compose them and also the possibility of their combined use. Protein isolates obtained from legume proteins, such as soybeans and peas, and also whey proteins, can be used due to the nutritional and functional appeal they present. These protein sources, although well studied for their functional characteristics, have their functionality dependent on the matrix in which they are inserted. Thus, the objective of this study was to develop cookies with high protein content, and good protein quality and availability; correlating the sources of proteins used with rheological, process, technological, sensorial and nutritional characteristics, firstly in biscuits type cookies, using whey (HW) and collagen (HC) protein hydrolysates and; and, then, in sweet molded cookies, using pea (PPI), soybean (SPI) and whey (WPI) protein isolates. Both hydrolysates and isolates weakened wheat flour doughs, limiting substitutions to 5 and 10%, respectively, to maintain the viscoelastic characteristics of wheat flour doughs. However, for the production of cookies, larger substitutions proved to be adequate. For cookie production, water addition to the dough was increased by the isolates and decreased by the hydrolysates, also modifying the baking time. Technological characteristics were also altered, such as increased moisture and water activity, as well as browning of biscuits. The dimensions were also affected: hydrolysates increased the diameter and isolates decreased the thickness and increased the expansion factor. Even with the modifications,
12 the biscuits were well accepted, presenting scores for appearance and color that were equal to or better than the control. However, a bitter taste was detected, mainly with the addition of the hydrolysates, thus reducing the purchase intent. Despite this, biscuits of desirable quality were produced and reached higher protein content and quality, as well as high digestibility values. The addition of 10% HW/10% HC allowed doubling the protein content, with an increase of 66% in lysine content. And the assays with 6% PPI/24% SPI/6% WPI and 15% PPI/15% SPI/15% WPI, could be considered as “protein sources”, with their protein and lysine levels increased by 68 and 70%, and 56 and 62%, respectively.
13
SUMÁRIO
CAPÍTULO 1 ... 14
INTRODUÇÃO GERAL ... 15
CAPÍTULO 2 ... 21
PROTEIN ENRICHMENT OF BISCUITS: A REVIEW ... 22
CAPÍTULO 3 ... 46
PROTEIN ENRICHMENT OF WHEAT FLOUR DOUGHS: EMPIRICAL RHEOLOGY USING PROTEIN HYDROLYSATES ... 47
CAPÍTULO 4 ... 71
NUTRITIONAL ENRICHMENT OF COOKIES USING PROTEIN HYDROLYSATES ... 72
CAPÍTULO 5 ... 102
EMPIRICAL RHEOLOGY OF WHEAT FLOUR DOUGHS WITH DIFFERENT PROTEIN ISOLATES FOR APPLICATION IN CEREAL-BASED PRODUCTS ... 103
CAPÍTULO 6 ... 130
CORRELATION BETWEEN SRC® AND MIXOLABTM PARAMETERS AND PROCESS AND TECHNOLOGICAL PARAMETERS OF PROTEIN ENRICHED-COOKIES………...131
CAPÍTULO 7 ... 163
SENSORY AND NUTRITIONAL EVALUATION OF SWEET MOLDED COOKIES WITH PROTEIN ISOLATES ………..164 CAPÍTULO 8 ... 185 DISCUSSÃO GERAL ... 186 CAPÍTULO 9 ... 199 CONCLUSÃO GERAL ... 200 REFERÊNCIAS BIBLIOGRÁFICAS ... 202 APÊNDICES ... 218 APÊNDICE 1 ... 219 APÊNDICE 2 ... 222 ANEXOS ... 224 ANEXO 1 ... 225 ANEXO 2 ... 226 ANEXO 3 ... 227 ANEXO 4 ... 228 ANEXO 5 ... 234
14
− CAPÍTULO 1 –
Introdução Geral
Este capítulo apresenta uma introdução geral sobre o tema que será abordado na tese, bem como apresenta os objetivos da pesquisa, e faz-se uma breve explicação sobre a organização da tese.
15 Capítulo 1 1. INTRODUÇÃO GERAL
Embora não constituam um alimento básico como o pão, os biscoitos são uma parte muito significativa da indústria de alimentos. Na maioria dos países do mundo são aceitos e consumidos por pessoas de qualquer faixa etária. Seu sucesso pode ser atribuído a alguns fatores como: vida de prateleira relativamente longa, a qual permite que sejam produzidos em grande quantidade e largamente distribuídos; conveniência; propriedades sensoriais, valor agregado, entre outros (MANLEY, 2005; VILLEMEJANE et al., 2015). Além disso, na maioria das vezes, são vistos como uma fonte agradável de energia, devido aos seus altos teores de açúcar e gordura, e não como um elemento importante de nutrição (MANLEY, 2005).
Todavia, mesmo diante deste cenário, a venda de biscoitos tem permanecido alta (MANLEY, 2005, ABIMAPI, 2019). Os biscoitos tidos como saudáveis têm ganhado espaço no mercado, evidenciando uma oportunidade de expansão da produção (M DIAS BRANCO, 2019). Oportunidade esta, que está ligada tanto ao desenvolvimento de biscoitos com calorias reduzidas, com alegações comuns de: sem gordura, com baixo teor de gordura, gordura reduzida, sem adição de açúcar, etc.; quanto através da utilização deste produto como um meio ideal para veículo de diversos nutrientes, como proteínas, fibras, vitaminas e minerais (MANLEY, 2005).
Neste sentido, enriquecer biscoitos com proteínas não só melhora as propriedades nutricionais, aumentando o consumo de proteínas e compensando deficiências de certos aminoácidos limitantes (o que depende da fonte proteica utilizada), tais como a lisina; mas também pode atender às necessidades específicas de grupos-alvo e vulneráveis da população, que desnutridas (GANI et al., 2015b).
Como principal matéria-prima para a produção de biscoitos, a farinha de trigo pode ter sua qualidade proteica melhorada pela adição de ingredientes e/ou matérias-primas ricas em proteínas (GANI et al., 2015a). Biscoitos preparados a partir de farinhas compostas já têm sido utilizados como veículos de fortificação em proteínas, devido a sua longa vida de prateleira e alta aceitabilidade (TSEN et al.1973; EL-DASH et al., 1994; AMIN et al., 2016). Entretanto, há ainda a necessidade de se estudar mais a fundo a influência da adição de fontes proteicas nas propriedades reológicas da
16 Capítulo 1 massa e também no processo, para então correlacionar estes fatores à qualidade final do produto, o qual se almeja oferecer a alegação de fonte ou de rico em proteínas.
Como alternativas para o enriquecimento, podem ser utilizados os hidrolisados e isolados proteicos, ainda pouco estudadas. Quantidades significativas de proteínas na forma de peptídeos na dieta podem ser absorvidas mais rapidamente do que na forma de aminoácidos livres (KEOHANE et al., 1985; BOZA et al., 2000; FOEGEDING et al., 2011). Além disso, a hidrólise pode diminuir a alergenicidade, que muitas vezes pode ser um fator preocupante em enriquecimento proteico. Teoricamente, a hidrólise extensiva destrói os epítopos, resultando em produtos hipoalergênicos (MAHMOUD, 1994; FOEGEDING et al., 2011).
Já os isolados, embora tenham sido amplamente estudados separadamente em termos de características funcionais, têm sua funcionalidade muito dependente do ambiente em que suas proteínas estão inseridas (FOEGEDING et al., 2011). Portanto, é importante estudar seu comportamento na matriz do produto, em todas as etapas do processo, e verificar a interação de diferentes fontes de proteína que permitem a melhor correlação de sua funcionalidade no produto final (NOGUEIRA e STEEL, 2018).
2. OBJETIVOS 2.1. Objetivo Geral
O objetivo geral deste estudo foi desenvolver biscoitos (cookies e biscoitos moldados doces) com alto teor de proteínas e de boa qualidade e disponibilidade proteica, através da utilização da combinação de hidrolisados proteicos de soro de leite e colágeno e; de isolados proteicos de ervilha, soja e soro de leite.
2.2. Objetivos Específicos
Caracterizar as fontes proteicas utilizados no enriquecimento;
Avaliar a reologia de massas de farinha de trigo adicionadas de hidrolisados proteicos de soro de leite e de colágeno;
17 Capítulo 1 Avaliar a influência dos hidrolisados proteicos de soro de leite e de colágeno na produção e na qualidade tecnológica, sensorial e nutricional de cookies;
Avaliar a influência dos hidrolisados proteicos de soro de leite e de colágeno nos cookies durante a estocagem;
Avaliar a reologia de massas de farinha de trigo adicionadas de isolados proteicos de ervilha, soja e soro de leite a fim de definir as quantidades máximas de adição;
Avaliar a influência dos isolados proteicos de ervilha, soja e soro de leite na produção e na qualidade tecnológica, sensorial e nutricional de biscoitos moldados doces.
3. ORGANIZAÇÃO
O presente documento está organizado em capítulos, sendo que alguns deles correspondem a artigos publicados e/ou submetidos a periódicos da área, tal como está especificado na capa de cada um, e outros correspondem a artigos prontos para a submissão. A disposição dos capítulos corresponde à ordem cronológica na qual a pesquisa foi realizada. No Capítulo 1 – Introdução Geral, apresenta-se uma explicação geral do documento, para que o leitor consiga ter uma visão global e um melhor entendimento da interligação entre os capítulos.
No Capítulo 2 – Protein enrichment of biscuits: a review, é apresentada uma revisão sobre o enriquecimento proteico de biscoitos: fontes utilizadas e os efeitos deste enriquecimento na reologia das massas, no processo e nas características tecnológicas, sensoriais e nutricionais deste produto. Neste capítulo foram reunidas informações das publicações existentes sobre este tema.
Através da análise feita sobre o tema, foi decidido estudar o enriquecimento proteico com fontes potenciais: hidrolisados e isolados proteicos. Os Capítulos 3 e 4, correspondem ao estudo da utilização dos hidrolisados proteicos de soro de leite e colágeno na produção de cookies. No Capítulo 3 – Protein enrichment of wheat flour doughs: empirical rheology using protein hydrolysates, estudou-se a reologia empírica de massas de farinha de trigo substituídas por concentrações de 0 a 20% de hidrolisados
18 Capítulo 1 proteicos de soro de leite e colágeno, de acordo com um delineamento composto central rotacional (DCCR) 22. Este trabalho possibilitou verificar o comportamento das massas com a adição dos hidrolisados e, assim, predizer a melhor aplicação. O Capítulo 4 – Nutritional enrichment of cookies using protein hydrolysates, apresentou os resultados obtidos do enriquecimento proteico de cookies utilizando os hidrolisados proteicos de soro de leite e colágeno: parâmetros de processo, características tecnológicas, sensoriais e nutricionais dos biscoitos, assim como avaliação durante a estocagem.
Já, os Capítulos 5, 6 e 7 correspondem ao estudo do desenvolvimento de biscoitos moldados doces através da substituição da farinha de trigo pelos isolados proteicos de ervilha, de soja e de soro de leite. O Capítulo 5 – Empirical rheology of wheat flour doughs with different protein isolates for application in cereal-based products, apresenta a avaliação da reologia empírica de massas de farinha de trigo adicionadas de isolados proteicos de ervilha, de soja e de soro de leite, até a concentração máxima possível. No Capítulo 6 – Correlation between SRC® and MixolabTM parameters and process and technological parameters of protein-enriched cookies, avaliaram-se os biscoitos produzidos com os isolados proteicos de ervilha, de soja e de soro de leite, de acordo com um delineamento composto central rotacional (DCCR) 23. Os resultados foram correlacionados com os parâmetros obtidos nas análises de SRC® e MixolabTM, que também seguiram este delineamento, uma vez que estas análises podem ajudar a direcionar a melhor aplicação. E, o Capítulo 7 – Sensory and nutritional evaluation of sweet molded cookies supplemented with protein isolates mensurou a aceitação sensorial e alguns aspectos nutricionais de cinco formulações de biscoitos previamente escolhidas do delineamento do artigo anterior, a fim de completar a análise geral do enriquecimento: desde a influência na reologia das massas até a aceitação do consumidor e a efetividade da proteína adicionada (teor, qualidade e disponibilidade proteica).
No Capítulo 8 – Discussão Geral, apresenta-se uma síntese dos resultados mais importantes obtidos no estudo da reologia das massas, no processo e na caracterização tecnológica, sensorial e nutricional dos biscoitos produzidos, tanto com os hidrolisados proteicos de soro de leite e de colágeno, quanto com os isolados proteicos de ervilha, de soja e de soro de leite, assim
19 Capítulo 1 como da correlação realizada. E, no Capítulo 9 – Conclusão Geral apresentam-se algumas conclusões, condensando as informações mais importantes do estudo.
Por fim, são apresentadas todas as referências bibliográficas utilizadas ao longo deste documento, assim como os apêndices e os anexos.
4. REFERÊNCIAS BIBLIOGRÁFICAS
ABIMAPI. Biscoitos - Estatísticas. Disponível em: <https://www.abimapi.com.br/estatistica-biscoito.php>. Acesso em: 19 fev. 2019.
AMIN, T.; BASHIR, A.; DAR, B. N.; NAIK, H. R. Development of high protein and sugar-free cookies fortified with pea (Pisum sativum L.) flour, soya bean (Glycine max L.) flour and oat (Avena sativa L.) flakes. International Food Research Journal, v.23, n.1, p.72-76, 2016.
BOZA, J. J.; MOËNNOZ, D.; VUICHOUD, J.; JARRET, A. R.; GAUDARD-de-WECK, D.; BALLÈVRE, O. Protein hydrolysate vs free amino acid-based diets on the nutritional recovery of the starved rat. European Journal of Nutrition, v.39, n.6, p.237-243, 2000.
EL-DASH, A.; CABRAL, L. C.; GERMANI, R. Uso de farinha mista de trigo e soja na produção de pães. In: EMBRAPA. Coleção Tecnologia de Farinhas Mistas. Brasília: Empresa Brasileira de Pesquisa Agropecuária, v.3, 1994, 47p.
FOEGEDING, E.A., LUCK, P., VARDHANABHUTI, B. Whey protein products. In: J. FUQUAY, J.; FOX, P.; MCSWEENEY, P. (Eds.). The encyclopedia of dairy sciences. 2nd. Oxford: Academic Press, 2011. 873– 878p.
GANI, A.; BROADWAY, A. A.; AHMAD, M.; ASHWAR, B. A.; WANI, A. A.; WANI, S. M.; MASOODI, F. A.; KHATKAR; B. S. Effect of whey and casein protein hydrolysates on rheological, textural and sensory properties of cookies. Journal of Food Science and Technology, v.52, n.9, p.5718-26, 2015a. GANI, A.; BRODWAY, A. A.; MASOODI, F. A.; WANI, A. A.; MAQSOOD, S.; ASHWARI, B. A.; SHAH, A.; RATHERI, S. A.; GANI, A. Enzymatic hydrolysis of whey and casein protein- effect on functional, rheological, textural and sensory properties of breads. Journal of Food Science and Technology, v.52, n.12, p.7697–7709, 2015b.
KEOHANE, P.P.; GRIMBLE, G. K.; BROWN, B.; SPILLER, R. C.; SILK, D. B. A. Influence of protein composition and hydrolysis method on intestinal absorption of protein in man. Gut, v.26, p.907-913, 1985.
20 Capítulo 1 M DIAS BRANCO. Mercado de Biscoitos, Massas e Grãos. Disponível em: <http://ri.mdiasbranco.com.br/conteudo_pt.asp?idioma=0&conta=28&tipo=3003 #1>. Acessado em: 07 jan. 2019.
MAHMOUD, M. I. Physicochemical and functional properties of protein hydrolysates in nutritional products. Food Technology, v.48, n.10, p.89-113, 1994.
MANLEY, D. Technology of biscuits, crackers and cookies. 3. Ed. Cambridge: Woodhead Publishing in Food Science and Technology, 2005, 499p.
NOGUEIRA, A.C.; STEEL, C.J. Protein enrichment of biscuits: a review. Food Reviews International, v.34, n.8, p. 796-809, 2018.
TSEN, C. C.; PETERS, E. M.; SCHAFFER, T.; HOOVER, W.J. High protein Cookies. 1. Effect of soy fortification and surfactants. Baker’s Dig., v.57, n.4, p.34, 1973.
VILLEMEJANE, C.; WAHL, R.; AYMARD P.; DENIS, S.; MICHON, C. In vitro digestion of short-dough biscuits enriched in proteins and/or fibres, using a multi-compartmental and dynamic system (1): Viscosity measurement and prediction. Food Chemistry, v.182, p.55- 63, 2015.
21
− CAPÍTULO 2 –
Protein enrichment of biscuits: a review
Este capítulo apresenta uma revisão sobre o enriquecimento proteico de biscoitos: fontes utilizadas e os efeitos deste enriquecimento na reologia das
massas, no processo e nas
características tecnológicas, sensoriais e nutricionais deste produto.
Este capítulo foi publicado no periódico Food Reviews International, volume 34, número 8, p. 796-809, 2018 (https://doi.org/10.1080/87559129.2018.1441299), conforme Anexo 1.
22 Capítulo 2
Protein enrichment of biscuits: a review
Amanda de Cássia Nogueira1 & Caroline Joy Steel1*
1Department of Food Technology, School of Food Engineering, University of Campinas, Campinas,
São Paulo, Brazil.
*Corresponding author: steel@unicamp.br
ABSTRACT
Protein enrichment of biscuits aims to reach, through a product that is widely accepted among consumers, target groups that have greater needs of this nutrient and also consumers that seek products that provide more than basic nutrition. Several protein sources have been studied for this purpose and, although the use of flours in general is more common, protein concentrates, isolates and hydrolysates may be good alternatives. Although this reformulation seems simple, it is known that small variations in the formulations can cause important effects on dough rheology, the process, and the end product (technological and sensorial characteristics).
Keywords: protein, protein isolate, soybean, pea, whey.
INTRODUCTION
The search for products that offer health benefits is a consolidated trend. Traditional foods and foods that are widely consumed by the population are effective vehicles for nutrient incorporation and, thus, are targeted by this growing and increasingly demanding market. Among these foods, biscuits are potential enrichment vehicles, since they are widely consumed, present varied forms and flavors, have long shelf life, provide convenience, have pleasant aroma and taste, and they can be consumed as snacks or as a complement to other foods.(1)
Protein enrichment of biscuits fulfills the need for a higher content of this nutrient, since these products tend to have low protein contents (7-10%). Cereal products are enriched to improve their nutritional properties, increase protein
23 Capítulo 2 consumption or compensate for deficiencies of determined limiting amino acids such as lysine, methionine or tryptophan.(2,3)
Since the nutritional quality of a protein depends on the content of its essential amino acids and its digestibility, nutritional quality of biscuits can be improved by mixing wheat flour with other proteins of high content of limiting amino acids in wheat such as lysine.(4) Legume and whey proteins can be used as sources for protein enrichment of biscuits because of their protein quality and their nutritional and technological appeal.(5,6)
Biscuits
The name “biscuit” originated in France to describe a type of bread which, baked twice, became hard for better conservation,(1) and has changed a lot since then. It can be defined as a bakery product made from wheat flour, sugar and fat, and which has moisture content below 4% (and water activity below 0.3%).
Considered a traditional food with significant presence in many countries, it is consumed by people of almost all socioeconomic levels. Its success can be attributed to some factors such as: relatively long shelf life that allows large-scale production and widespread distribution, convenience, sensorial properties, and added value, among others.(1,7)
In general, biscuits are consumed for their interesting texture, aroma and taste, and for the pleasure they bring, as a snack or a complement to other foods. Usually, they are considered a good source of energy and not an important element of nutrition. Their high contents of sugar and fat have been a concern in public health, since they are often linked with risks of some diseases such as cardiovascular diseases, diabetes, and obesity.(1) Thus, biscuits with health claims have gained more attention in the market, showing an opportunity to expand production.(8) Biscuits with reduced calories and claiming no fat, low fat, reduced fat, no added sugar, etc., and enriched with several nutrients and/or functional ingredients, such as proteins, vitamins and minerals, and fibers, are more and more common on the market.(1)
Protein enrichment
Regarding the protein content, commercial biscuits contain around 7-10% protein, which is considered low.(9,10) Due to such low protein content, protein enrichment of biscuits and other cereal products is interesting to improve their
24 Capítulo 2 nutritional properties, increase protein consumption or compensate for deficiencies in certain limiting amino acids such as lysine. In many foods, lysine is the limiting amino acid not only due to the small amounts that are incorporated during protein biosynthesis, but also as a result of secondary chemical changes caused by factors such as light, heat, alkali and reducing sugars, making lysine nutritionally unavailable. Lysine is nutritionally available when the ε-amino group is free. If this group is blocked by a chemical bond, the protein segment next to the affected lysine residue may not be digested.(11,12) Therefore, refined wheat flour, as the main raw material of bakery products and responsible for their protein quality, can be improved with the addition of protein-rich ingredients and/or raw materials.(10)
Another factor to be considered in protein enrichment is protein-calorie malnutrition, which has been a serious problem in people whose diet consists mainly of starchy cereals or foods, especially in Afro-Asian countries. In addition, the current trend of population growth means that this malnutrition will keep growing in the future, unless well-planned measures are adopted to address this situation.(13)
Another factor is the satiety effect of proteins, in such a way that protein-rich diets are known to cause positive effects on body composition and metabolism.(14) Protein sources used to enrich biscuits
Several ingredients and raw materials have been used to improve the protein content of biscuits. Legumes, such as soybeans, peas, chickpeas and beans, have been used as protein sources to fortify biscuits,(5,6,15-26) considering they are rich in starch, protein and fiber, and contain sufficient amounts of vitamins and minerals, helping to fulfill health-related demands of conscious consumers.(25,27) In addition, regarding the contents of lysine and sulfur amino acids, cereal and legume proteins are nutritionally complementary.(28,29) Milk and whey proteins have also been used in protein enrichment and fortification of most bakery products because of their nutritional and functional characteristics.(10,26,30-32) Some fish species or byproducts have also been used for such purpose,(33-35) as well as other raw materials such as macambira,(36) Spirulina platensis,(37) brown flax seeds,(38) bee pollen,(39) sunflower seeds,(40) pumpkin seeds,(41) safflower(42) and cashew kernel.(43)
In general, there are more studies on composite flours (flours resulting from mixing two or more types of flour) for protein fortification.(25,44,45) However, protein isolates have been used as alternative protein enrichment sources, because they
25 Capítulo 2 present high protein content (>88%),(46-47) are easily digested by the human body and some are equivalent to the protein quality of milk, meats and eggs.(48) Although protein isolates have been widely studied separately in terms of functional characteristics, either technological or physiological, their functionality in a product depends on the environment in which these proteins are inserted.(49) Therefore, it is important to study their behavior in the product matrix, in all stages of the process, and verify the interaction of different protein sources that will allow the best correlation of their functionality in the final product.(10) Protein isolates from soybeans and whey have already been widely used in the food industry in general, mainly because of the high availability of their starting raw materials. Isolates, from sources such as peas and other legumes, have also been studied.
Considering the aforementioned information, we have decided to analyze in detail these three protein sources (soy, whey, pea), exposing a literature review focused on the effects of their products (flour, isolate and even protein hydrolysate) on the enrichment of biscuits, in several aspects: dough rheology, process, and technological, sensorial and nutritional characteristics of the end product.
Effects of protein enrichment On dough rheology
Addition of protein sources to wheat flour tends to alter dough rheology, since it dilutes gluten proteins, leading to a weakened protein network. The study that analyzed the addition of 3 to 5% soy protein isolate to wheat flour showed increased water absorption and resistance to extension and reduced development time, stability and extensibility.(50) Ammar et al.(31) reported an increase in water absorption and a decrease in development time and stability by adding 0.7% SPI. Tang and Liu(26) also observed an increase in water absorption in the Mixolab, adding 5 to 30% soy protein. A higher amount of water is used to achieve an excellent development of dough containing soy flour to avoid drying,(51) since this dough tends to be drier and more brittle.(6) Singh and Mohamed(52) also obtained reduced stability with the addition of gluten and soy protein isolate. The addition of 10 and 15% whey proteins resulted in decreased water absorption and reduced dough development time, and it significantly influenced the viscosity parameters measured in the Rapid Visco Analyser (RVA).(10) Sudha et al.(53) and Tang and Liu(26) reported a decrease in water absorption with the addition of whey protein concentrate. Nogueira et al.(54) obtained
26 Capítulo 2 reduced water absorption and stability by partially replacing wheat flour with whey protein hydrolysate. Parate et al.(55) observed the need for increased water addition to achieve an adequate consistency of the biscuit dough with the addition of 20 to 40% whey protein concentrate. The use of pea flour also resulted in increased water absorption.(3) However, dough prepared with 10, 20 and 30% pea flour was very similar to wheat flour dough in terms of consistency and handling characteristics.(6)
A summary of the studies found and the results obtained can be observed in Table 1. It can be seen that the addition of the protein sources greatly affects the rheological behavior of the dough; as there is almost always a change (either increase or decrease) caused by the addition of the different protein sources. The addition of flours seems to contribute to increasing WA, also due to the other components (fibers, for example) present in it. On the other hand, whey products (isolated, concentrated or hydrolyzed) tend to decrease this parameter, probably due to a lower water holding capacity or to a physical impediment to the hydration of wheat flour. In general, a weakening of the dough is observed with the addition of the protein sources. The behavior of the different protein sources in the pasting properties is very similar, since they influence the parameters mainly by the dilution of the starch present. It is also important to note here that, in addition to the influence of the protein sources, which can present different abilities to absorb/retain water, some ingredients of the biscuit formulations may also contribute to a greater or a lower absorption. This fact also helps to explain the differences found between studies. Formulations with different levels of sugar and fat, and also of their derivatives, for example, can strongly influence this parameter.
27 Capítulo 2 Table 1. Studies on the effect of soy, whey and pea as protein sources on rheological parameters of wheat flour doughs
Analysis Source / Concentration
(%) Results Reference
Farinograph
SPI / 0.7 Increased WA / Decreased DDT and S (31)
Soy flour / 0-15 Increased WA, DDT and S (53)
WPC / 0.7 Increased WA / Decreased DDT and S (31)
WPC / 0-15 Decreased WA and S (10)
WPC / 0-15 Decreased WA / Increased DDT (53)
WPH / 0-15 Decreased WA and S (10)
WPH / 0-20 Decreased WA / Increased DDT (54)
Pea flour / 0-10 Increased WA (3)
Mixolab Measurements
Soy protein / 0-30 Increased WA and MST from 10% / Did not change PT (26)
Whey protein / 0-30 Decreased WA and MST / Increased MDT and PT (26)
Alveograph Soy flour / 0-15 Increased P / Decreased L (53)
WPC / 0-15 Decreases P and L (53)
Pasting properties
Soy flour / 0-15 Increased PT / Decreased maximum, hold and final viscosities, breakdown and
setback (53)
WPC / 0-15 Decreased maximum, hold and final viscosities, breakdown and setback (10)
WPC / 0-15 Increased PT / Decreased maximum, hold and final viscosities, breakdown and
setback (53)
WPH / 0-15 Decreased maximum, hold and final viscosities, breakdown and setback (10)
WPH / 0-20 Increased PT / Decreased maximum, hold and final viscosities, breakdown and
setback (54)
SPI: soy protein isolate; WPC: whey protein concentrate; WPH: whey protein hydrolyzed; WA: water absorption; DDT: dough development time; S: stability; PT: pasting temperature; MST: Mixolab stability time; MDT: Mixolab development time; P: maximum pressure; L: extensibility.
28 Capítulo 2 On the process
Effects of protein sources on different biscuit production processes are still not very well understood. Scarce information is available in the literature on how these protein sources impact process parameters, and it is not clear if there is any process with better results for such enrichment. In addition, submitting these protein sources to processing, that is, to factors that interfere with the interactions of protein molecules and their conformational structure, leads to changes in their technological and physical-chemical properties,(56) which can be positive or negative for the process. For instance, an increase in water absorption can be considered a negative point in biscuit production, as it will lead to longer baking times. Shorter process times are desired, in order to achieve greater productivity.
Soy flour improves biscuit shaping. In the lamination stage, it helps to prevent hardening, producing more homogeneous dough, since it reduces dough elasticity and increases dough extensibility, as a result of the emulsifying power of lecithin found in soy flour.(1,51) During the dough modeling stage for biscuit production, formulations with higher content of defatted soy flour presented harder and more brittle dough and, therefore, of difficult modeling and handling,(6,19) which may also reduce the biscuit diameter.(19) As previously mentioned, the fact that the pea flour dough behaves very similarly to wheat flour dough means that no alteration would be required in the formulation for easier handling of biscuit dough containing this flour.(6)
Most of the studies found in the literature do not address the biscuit manufacturing process, since, in them, the biscuits are produced more manually. This fact often makes it impossible to acquire information that translates into a level of production on a larger scale. There are also different types of biscuits, derived from different processes (molded, laminated and wire-cut biscuits, for example). Thus, the behavior of these sources can be quite distinct in each of them, which makes the study of processes an important gap to be filled.
On the technological characteristics of biscuits
Besides increasing protein content, the sources used for such purpose can have different effects on the technological characteristics of biscuits. One example is biscuit dimensions. Gani et al.(10) did not observe any alteration in the spread factor (width/thickness) of biscuits enriched with up to 15% whey protein concentrate, unlike Wani et al.(57) and Tang and Liu(26) who mentioned an increase in this parameter with
29 Capítulo 2 whey protein. However, Parate et al.(55) observed reduced diameter and increased thickness of biscuits with 20 to 40% of the same protein. These variations can be due to the formulations and also to the processes used. Singh and Mohamed(52) also observed a negative correlation between biscuit diameter and protein content. McWatters(6), when using pea flour, did not observe any alteration to biscuit dimensions or weight; however, with soy flour, the author found reduced diameter and spread factor (width/height). With soy protein, Tang and Liu(26) found a decrease of the expansion factor with additions of 5 and 10% and an increase with 30%. At intermediate concentrations (15, 20 and 25%), this parameter was similar to the control test (without soy protein). The incorporation of other proteins interferes in the development of the gluten network and negative effects, such as the decrease in the spread ratio, are expected, especially when the addition of other proteins is greater than 5%.(6) However, when the addition is much greater than the gluten content, there can be a different behavior.(26) These authors, at higher concentrations of soy protein, observed a possible aggregation that induced the formation of a network, which helped increase the elasticity and extensibility of wheat flour, leading to an increase in the spread ratio. The soy protein network formed may also have conferred a protective effect on the partial structure of gluten, contributing to the gain of quality.(26) Kissel and Yamazaki(5) stated that the phenomenon of biscuit horizontal expansion is primarily physical and controlled by the ability of the components to absorb water.
Biscuit color may also change. The addition of whey protein resulted in darker biscuits,(10,26,55,57) as did the addition of soy protein isolate (SPI).(26,51) The replacement of wheat flour by soy flour and whey protein concentrate also had a significant effect on color development.(58) However, these authors stated that soy flour had a much less significant effect than whey protein concentrate. Whey protein concentrate probably favored the development of cookie color due to its high lactose content. The darkening of biscuits can be attributed to a higher degree of the Maillard reaction, due to a higher protein content and consequent interaction with sugars.(10) It is known that flavors developed through the Maillard reaction in the last stage of baking contribute to biscuit acceptance. However, it should be noted that, besides biscuit darkening, sometimes excessive, the condensation reaction between reducing
30 Capítulo 2 sugars and the amino group of the lysine side chain during the Maillard reaction leads to a great loss of available lysine.(58)
Increased protein concentrations in biscuits can also lead to increased hardness.(10,19) McWatters et al.(59) attributed a harder texture of biscuits to increased protein content and protein interaction with sugars during dough preparation and baking. Tang and Liu(26) observed greater hardness in their biscuits with whey protein up to 15% addition. With soy protein, only the concentrations of 20, 25 and 30% differed from the control, presenting lower hardness, probably due to a greater spread factor (and lower thickness).
Also regarding physical characteristics, biscuits containing pea flour were very similar to those produced with wheat flour, with no significant difference in diameter, height, spread factor, external appearance, texture and moisture content.(6)
Table 2 shows the main results obtained with the addition of these protein sources on technological characteristics of biscuits. In general, the moisture content of enriched biscuits increased. The variations observed in spread ratio and texture results may be due, not only to the addition levels, but also to the formulations and processes used. However, the protein sources seem to greatly influence these important quality parameters for biscuits. And with regard to color, the darkening caused by the addition of these protein sources is an already expected effect.
31 Capítulo 2 Table 2. Studies on the effect of soy, whey and pea as protein sources on composition and technological characteristics of cookies
Analysis Source / Concentration (%) Results Reference
Moisture
SPI / 0-20 Increased (17)
Soy flour / 0-10 Increased (25)
Soy flour / 0-20 Decreased (24)
Soy flour / 0-30 Without change (6)
WPC / 0-40 Increased (55)
WPC / 0-6 Increased (57)
Pea flour / 0-30 Without change (6)
Pea flour / 0-10 Increased (25)
Protein
SPI / 0-20 Increased / At the highest level of addition: increase of 39.5% (17)
Soy flour / 0-10 Increased / At the highest level of addition: increase of 27.8% (25)
Soy flour / 0-20 Increased / At the highest level of addition: increase of 38% (24)
Soy flour / 0-30 Increased / At the highest level of addition: increase of 49.3% (6)
WPC / 0-40 Increased / At the highest level of addition: increase of 65% (55)
WPC / 0-6 Increased / At the highest level of addition: increase of 31.3% (57)
Pea flour / 0-30 Increased / At the highest level of addition: increase of 25.7% (6)
Pea flour / 0-10 Increased / At the highest level of addition: increase of 15.8% (25)
Spread ratio
Soy protein / 0-30 Decreased up 10% / Without change in the other concentrations (26)
Soy flour / 0-30 Without change with 10% / Decreased with 20 and 30% (6)
WPC / 0-15 Without change (10)
WPC / 0-40 Decreased (55)
WPC / 0-6 Without change with 2% / Increased with 4 e 6% (57)
WPH / 0-15 Without change (10)
Whey protein / 0-30 Without change up 5% / Decreased in the other concentrations (26)
32 Capítulo 2 Continuation of Table 2
Texture
Soy protein / 0-30 Less hard from 20% (26)
WPC / 0-15 Harder (10)
WPH / 0-15 Harder (10)
Whey protein / 0-30 Harder from 15% (26)
Color
Soy protein / 0-30 Darkening (26)
Soy flour / 0-15 Darkening (58)
WPC / 0-15 Darkening (10)
WPC / 0-6 Darkening (57)
WPC / 0-15 Darkening (58)
WPH / 0-15 Darkening (10)
Whey protein / 0-30 Darkening (26)
33 Capítulo 2 On the sensorial characteristics of biscuits
Regarding sensorial characteristics, in most cases, the overall low acceptance of biscuits containing higher protein contents is attributed to the taste and darkening. According to Gani et al.,(10) consumers perceived a bitter taste in biscuits with concentrations above 5% whey protein concentrate, which can be attributed to the presence of bitter peptides, especially when using protein hydrolysates. Tang and Liu(26) also observed a decrease in all sensory parameter scores with the addition of whey protein, reporting that the highest concentration accepted was 10%. Parate et al.(55) also mentioned the development of roughness on the surface of biscuits with increased whey protein concentrate level, leading to reduced acceptance of biscuit appearance. Also according to these authors, an addition of up to 25% whey protein concentrate allows the production of good quality biscuits. Since taste has a great effect on sensory acceptance, it can be said that formulations richer in ingredients tend to have greater acceptance. This explains the higher level of protein substitution achieved by Parate et al.,(55) compared to Gani et al.(10) and Tang and Liu,(26) for example. The formulation of Parate et al.(55) included diverse ingredients that collaborate with the taste (sugar, condensed milk, invert syrup, liquid glucose and flavor), while the others counted only with sugar and/or dextrose.
As for soy protein, Tang and Liu(26) achieved good sensory acceptance of cookies with concentrations of 10, 20 and 30%. Using soy protein isolate (SPI), Mohsen et al.(17) did not find significant differences in color acceptance among all cookie samples with up to 15% SPI, while supplementation of cookies with up to 10% SPI increased acceptance of all other sensory attributes (aroma, taste, crispness and overall acceptability). The low overall acceptability of cookies containing 20% SPI was attributed to less crispiness and more darkening. And even after three months, the sample supplemented with 10% SPI was the most preferred. With soy flour, Farzana and Mohajan(24), incorporating 10 to 20% soybean flour, achieved good overall acceptability. However, McWatters(6) obtained, for cookies containing 20 and 30% soy flour, low scores for appearance, texture and flavor, because of the thickness, hardness, raw bean flavor and low expansion properties. These properties also prevented the development of a typical surface of biscuits, that is, without roughness.
34 Capítulo 2 The addition of protein sources may also alter the aroma of cookies. Mohsen et al.,(17) for example, observed variations in the number and content of most of the volatiles identified by adding SPI in this product. According to these same authors, among the investigated samples, the cookies containing 10% SPI had a high content of volatile compounds, such as pyrazines and pyranones, which are considered aroma markers of these products. The concentration of pyrazines is related to the development of roasted flavor in thermally treated cereal products,(60) whereas that of pyranones, such as maltol (3-hydroxy-2-methyl-4(H)-pyran-4-one) or DDMP (2,3-dihydro-3,5-dihydroxy-6-methyl-4(H)-pyran-4-one), is associated with a pleasant sweet aroma.(61) Regarding the volatiles from lipid degradation, the fortification with 5% SPI revealed a considerable increase of these volatiles, followed by a gradual decrease with the increase of SPI content. This apparent decrease in the volatiles derived from lipids can be attributed to an increase in the formation of products derived from the Maillard reaction.(17) According to Mohsen et al.(17), the differences in aroma and taste among the cookie samples could be correlated to the changes in generated volatiles during the baking process.
McWatters(6), when adding 10, 20 and 30% pea flour to the biscuit dough, obtained high-quality sensorial scores for appearance, with no significant difference in relation to the control (100% wheat flour). In color and aroma scores, pea flour practically had no effect, and in texture scores, a slight reduction was observed with higher contents of this flour. These results showed the possibility to add up to 30% pea flour and still maintain biscuit quality. According to Kamaljit et al.,(3) the addition of up to 5% pea flour did not affect the sensorial characteristics of biscuits and improved their nutritional quality. Amin et al.(25) also obtained high sensory acceptance scores for cookies with 5 and 10% pea flour.
A summary of the results obtained regarding the sensorial properties can be observed in Table 3. Sensory acceptance of soybean sources presented different results, where some studies presented good scores for the parameters analyzed, while others did not (even with similar levels of addition). Despite this, the soy sources had greater sensory acceptance than those of whey and pea. The studies with whey proteins and pea flour showed a decrease of the scores for the sensorial parameters and a great variation in the maximum quantity accepted. This variation can be linked to differences in the formulation. It is known that differences in sugar
35 Capítulo 2 and fat contents, as well as their derivatives, in the formulations, can influence the taste and, consequently, the sensorial acceptance of the final product. A great challenge in the sensorial aspect is to mask the residual flavor of the protein enriched products and, thus, to allow greater incorporations.
On the nutritional characteristics of biscuits: As expected, the addition of protein sources caused a great increase of this nutrient in the biscuits (Table 2). However, protein quality is related to its content of essential amino acids, which should be higher than the reference levels defined by the Food and Agriculture Organization/World Health Organization/United Nations University (FAO/WHO/UNU),(62) and protein digestibility. In this sense, the nutritional quality of a protein with essential amino acid deficiency can be improved by mixing the protein with another protein that is rich in that specific amino acid, such as when cereal proteins (with lysine deficiency) are mixed with legume proteins (with methionine deficiency). However, it should be noted that an excessive consumption of any specific amino acid can lead to “amino acid antagonism” or toxicity, which results in a greater need for other essential amino acids, in addition to possible growth inhibition, leading to pathological conditions.(4)
Although the content of amino acids is the primary indicator of protein quality, the true quality also depends on the level of utilization of these amino acids in the body. The protein availability of milk, peas, wheat flour and SPI, for example, is 95, 88, 86 and 95%, respectively.(62) Several factors, such as protein conformation, anti-nutritional factors and processing, affect this availability.(4) Partial thermal denaturation of proteins usually improves the digestibility and bioavailability of essential amino acids.(4)
36 Capítulo 2 Table 3. Studies on the effect of soy, whey and pea as protein sources on sensorial characteristics of cookies
Analysis Source / Concentration (%) Results Reference
Sensory properties
SPI / 0-20 Desirable scores / Maximum amount accepted: 20% (17)
Soy protein / 0-30 Desirable scores / Maximum amount accepted: 30% (26)
Soy flour / 0-10 Decreased of scores / Maximum amount accepted: 5% (25)
Soy flour / 0-20 Desirable scores / Maximum amount accepted: 15% (24)
Soy flour / 0-30 Decreased of scores from 20% / Maximum amount accepted: 10% (6)
WPC / 0-15 Decreased of scores / Maximum amount accepted: 5% (10)
WPC / 0-40 Decreased of scores / Maximum amount accepted: 25% (55)
Whey protein / 0-30 Decreased of scores / Maximum amount accepted: 10% (26)
WPH / 0-15 Decreased of scores / Maximum amount accepted: 5% (10)
Pea flour / 0-30 Decreased of scores / Maximum amount accepted: 10% (6)
Pea flour / 0-10 Decreased of scores / Maximum amount accepted: 5% (25)
37 Capítulo 2 Most plant-based protein isolates and concentrates present anti-nutritional factors, such as trypsin and chymotrypsin inhibitors, which may impair the complete hydrolysis of legume proteins by pancreatic proteases,(4) affect the digestibility, absorption or utilization of nutrients, and cause harmful effects to health if ingested at high concentrations.(63) Peas have much lower activity levels of trypsin inhibitors and haemagglutinins or lectins when compared to soybeans.(64) Other anti-nutritional factors are also present in plant-based proteins, such as tannins and phytates. Tannins are considered as anti-nutrients because of the adverse effect on protein digestibility. Phytates interact with basic residues of proteins, participating in the inhibition of digestive enzymes such as pepsin, pancreatin and α-amylase.(4,65) However, when these proteins are subjected to a thermal treatment, these compounds are partially or totally eliminated.(4,66)
The presence of allergens in various protein raw materials can cause allergic reactions in children and adults.(4) Cow’s milk is the most common allergen for infants, with α-lactalbumin considered the main allergen.(67) Among legumes, some of the soybean fractions present allergenic activity, and the 2S fraction was reported as the most allergenic among the components of soy proteins.(68) However, these allergens, such as those from soybeans and milk, also become innocuous by denaturation when submitted to thermal treatment.(4,67)
Proteins can undergo several chemical changes during processing.(4) The interaction of proteins with polysaccharides and fibers can reduce the rate and degree of protein hydrolysis.(69) Lysine, for example, which is already limiting in cereal proteins, can have its availability further reduced. The condensation reaction between reducing sugars and the amino side-chain of lysine during the Maillard reaction leads to a severe loss of lysine availability.(58) Pérez et al.(58) observed that the loss of lysine availability increased linearly with the incorporation of whey protein concentrate and decreased with increasing water in the formulation. According to these same authors, the positive correlation between loss of lysine availability and whey protein concentrate was expected since the whey protein concentrate used contained high levels of lactose. Another interaction that affects protein structure is the protein-phenolic interaction, which may decrease protein bioavailability.(70,71) Phenolic compounds can bind to proteins and thus their bioavailability may be significantly reduced.(72)
38 Capítulo 2
The addition of proteins to enrich biscuits, whether in the form of composite flours (more common) or protein concentrates, isolates or hydrolysates, greatly influences dough behavior and the technological characteristics of the final product. In general, it leads to a weakened dough, changing its viscosity (pasting properties), since the gluten proteins and the starch are diluted. During the process, among the scarce information found, the emulsifying effect of soy flour is observed during lamination. Regarding technological characteristics, protein enrichment causes changes in biscuit dimensions, color and texture, and it often generates a bitter aftertaste, in a sensorial perspective. Nutritional strategies chosen involve the challenge of obtaining biscuits with higher protein content and quality that also allow the availability of this nutrient to the human body.
Studies that used soybean and pea flours, soy protein isolate, as well as whey hydrolysate and concentrate, were found in the literature. However, even with the evidence from the studies that used these protein sources, their effects on biscuit production processes are still not very well understood, since few studies have analyzed these effects or compared the various processes, especially regarding the molding steps. In addition, there is need for studies that analyze the technological effects and the protein availability in the final product.
ACKNOWLEDGEMENT
We would like to thank the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for the Doctorate Program scholarship granted to author Amanda de Cássia Nogueira and the Research Productivity scholarship granted to author Caroline Joy Steel. The authors also thank Espaço da Escrita – Coordenadoria Geral da Universidade – UNICAMP – for the language services provided.
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39 Capítulo 2
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