There are various products that can be obtained from ginger (Zingiber officinale Roscoe) rhizomes, such as dried products, being difficult to choose the best option for antioxidant purposes. In this study, three different dried forms of ginger rhizomes (freshly dried, dried and powder dried) were characterized in terms of chemical composition including individual profiles in sugars, organic acids, fatty acids, tocopherols, and antioxidants (phenolics and flavonoids). The in vitro antioxidant properties (free radicals scavenging activity, reducing power and lipid peroxidation inhibition) of their methanolic extracts were also evaluated. The results of this study indicate that the ginger form has significant influence in chemical and antioxidantparameters of the plant; dried ginger (DG) proved to be the best choice. Overall, this study could help the consumer in the selection of the most suitable option regarding antioxidant purposes.
Turgay et al. showed that the levels of oxidative stress and antioxidantparameters in erythrocytes and plasma of Turkish patients with systemic lupus ery thematosus (SLE) were not significantly different between active and inactive SLE. These authors found that these para- meters did not influence SLE disease severity but could be pa thogenetic factors for SLE etiology. Moreover, the- re were statistically significant differences between the SLE and control groups, though the most important li- mitation of the study was the small cohort size 13 .
High doses of DON in porcine blood in vitro influenced content of total protein and count of LYM. Lower doses of DON influenced activity of GPx and SOD. Other studied parameters were not affected by DON. The results from this study determined levels of deoxynivalenol toxicity. Given that DON is the most occuring fumonisine and there are not many studies in vitro about its effects on biochemical, haematological, prooxidant and antioxidantparameters in porcine blood, thus it is neccessary to be examined further.
shelf-life, had no effect on physical and organoleptic properties and was a cheap alternative to other conventional conservation methods. Regarding chestnuts, gamma radiation has been applied on them, mainly in Asian varieties ( Chung et al., 2004; Imamura et al., 2004; Iwata et al., 1959; Guo-Xin et al., 1980; Kwon et al., 2004 ) and recently in European varieties ( Antonio et al., 2011a, b, c; Barreira et al., 2012; Calado et al., 2011; Fernandes et al., 2011a, b; Mangiacotti et al., 2009 ) (Table 1). It has been already approved as a commercial technique in South Korea, for sprouting or rooting inhibition (0.25 kGy) ( Chung et al., 2004 ) and for quarantine disinfestations (0.50 kGy) ( Kwon et al., 2004 ). Nevertheless, it is important to evaluate the effects of gamma radiation on biological, physico-chemical, nutritional and antioxidantparameters, and also the application of standards to detect if a food product was irradiated or not.
Electron beam irradiation is used mainly for food products with low density and the equipment can be easily connected/disconnected. Otherwise, gamma irradiation is mainly used for large volumes (Fernandes et al., 2014; Van Calenberg et al., 1998) . Arenaria montana L. is a flowering plant belonging to the Caryophyllaceae family, native to mountainous regions of southwestern Europe. It is used in the Portuguese traditional medicine, acting therapeutically as an anti-inflammatory and diuretic, being mainly ingested in the form of infusion, prepared from the leaves, stems and flowers ( Timité et al., 2011; Carvalho, & Morales, 2013 ). Moreover, we previously described its antioxidant potential and richness in bioactive phytochemicals ( Pereira et al., 2014 ). In the present study, the objective was to evaluate the effects of irradiation (gamma and electron beam) at different doses (1 and 10 kGy) in nutritional, chemical and antioxidantparameters of A. montana.
Regarding ED (Figure 3A), function 1 (means of canonical variance (MCV), 0 kGy: - 18.168; 0.5 kGy: -34.190; 1 kGy: 27.782; 6 kGy: 24.577) and function 2 (MCV, 0 kGy: 19.436; 0.5 kGy: -14.209; 1 kGy: -1.322; 6 kGy: -3.905) separated primarily 0 and 0.5 kGy from the remaining doses, indicating that fructose, δ-tocopherol, C14:0 C6:0, C15:0, C16:0, C16:1, C17:0, C18:1, C20:5, C22:1, trehalose and α-tocopherol are the parameters with highest variation among non-irradiated samples or samples irradiated with 0.5 kGy and those irradiated with higher doses (Table 6). Function 3 was effective to separate 1 and 6 kGy (MCV, 0 kGy: 0.719; 0.5 kGy: -1.120; 1 kGy: -10.961; 6 kGy. 11.363), with reducing power (RP) (Fe 3+ /Fe 2+ ), β-tocopherol, C10:0, C12:0, C18:2, C20:0, C20:1 and C20:3 (Table 6) as the variables more affected by the increase from 1 to 6 kGy. On the other hand, nutritional parameters were the least affected by ED, as can be concluded from the low percentages of accurately classified groups (56.5% for the original groups and 40.7% for the cross-validation procedure) and verified on the plot of the means of canonical variance (Figure 3B), that do not individualize any specific group.
Many studies have applied gamma irradiation to a range of mushrooms including cultivated (Jiang, Luo, Chen, Shen, & Ying, 2010; Sommer, Schwartz, Solar, & Sontag, 2010) and, more recently, wild species (Fernandes et al., 2012a; Fernandes et al., 2012b). In those two studies of our research group, the effects of gamma irradiation on chemical composition, antioxidant activity and physical parameters of fresh Lactarius deliciosus wild edible mushroom were evaluated, being concluded that up to 1 kGy this technology was effective in maintaining chemical composition and controlling the deterioration of fresh samples.
experimental groups (E1–E6) in comparison with the control group (C). The lowest activity of SOD was observed in E5 and E6 groups in comparison with the control group (C) where quercetin in combination with T-2 toxin was applicated, and experimental groups where quercetin in various doses (E1-E4) was applicated, but without statistical significance (P>0.05). It is known, that natural substances can cause changes in antioxidant status. Seven et al. (2010) found that vitamin C and propolis decreased the SOD activity and showed a tendency to reduce CAT (catalase) and GSH (glutathione) levels. In different study Vilà et al. (2002) found that α-tocopherol was significantly lower for the T-2 toxin treated mice.
Nowadays there is a growing scientific interest in irradiation-induced modifications of antioxidant properties and compounds responsible for such effects. The antioxidant activity is strongly linked the presence of phenolic compounds [ 9 – 12 ], secondary metabolites frequently found attached to sugars (glycosides), which increases their water solubility. These compounds have the ability to donate a hydrogen atom from the aromatic hydroxyl group to a free radical and/or the capacity to support an unpaired electron in their aromatic structures. Therefore, the methods used to evaluate the antioxidant activity can be classified according to the mechanism of action, i.e., single-electron transfer or hydrogen atom transfer [ 13 ]. However, phenolic compounds, organic acids and other bioactive constituents may be affected by irradiation treatment if applied inappropriately. It is known that ionizing radiation interacts with water molecules generating free radicals, in a reaction commonly known as radiolysis [ 14 ]. These free radicals can then interact with different biomolecules, leading to breakdown of chemical bonds and changes in their structure and, consequently, in the bioactivity and extractability from the plant material. The referred compounds may also be affected by the direct impact of the gamma-rays [ 14 , 15 ]. As a consequence, the color of the processed samples may change. However, this quality attribute is directly related to consumers’ appreciation of a product, as they tend to associate its color with its taste, hygienic safety, shelf-life and personal satisfaction [ 16 , 17 ]. A very stringent plant selection based on color parameters also occurs in the food, pharmaceutical and cosmeceutical industries [ 18 ]. Therefore, the color evaluation is important in quality control parameter of irradiated products.
Different synthetic antioxidants are used nowadays in food industry, which can sometimes pose problems for the human health. The use of substances such as butylated hydroxyanisole, butylated hydroxytoluene and tertiary- butylhydroquinone is discouraged due to their negative health effects (Lee et al., 2006), while the interest focuses on the use of natural antioxidants. However, more research is necessary to determine the stability of extracts containing grape phenolics during various technological treatments and to determine whether their antioxidant properties and their colour are not drastically modified by time and temperature. Thus, the objective of this study is to determine the influence of different temperature and time values and storage time and conditions on the antioxidant activity and colour parameters of ethanolic grape marc extract.
levels of bioactive compounds such as phenols and carotenoids. Among the methods used to determine antioxidant activity for free radicals scavenging, the DPPH radical, ABTS and FRAP methods are the fastest. In some works the antioxidant activity is related to the content of phenols, flavonoids and carotenoids; however, there might be other compounds with antioxidant properties (vitamins, enzymes, minerals) in the sample matrix (SERRANO et al., 2007).
Currently, the search for antioxidant peptides from natural sources has gained growing interests since antioxidant peptides can act as free radical scavengers, peroxide decomposers, metal inactivators, or oxygen inhibitors to protect the body against reactive oxygen species (ROS) (Xue et al., 2015). Besides, antioxidant peptides also showed great potential in applications as food additives (Taheri et al., 2014) to replace synthetic antioxidant such as propyl gallate (PG), butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and tert-butylhydroquinone (TBHQ) (Liu et al., 2018). Enzymatic hydrolysis method has been proven to be an effective way of extracting antioxidant peptides from various fish proteins. For example, previous reports have shown anchovy fish (Wang et al., 2018), tilapia (Sun et al., 2013), cod (Girgih et al., 2015), and croceine croaker fish (Chi et al., 2015) can be sources for extracting antioxidant peptides.
Furthermore, the coating roughness and finishing layer can also influence the drying process (CULTRONE; SEBASTIÁN; ORTEGA HUERTAS, 2007, GRILO et al., 2014). A painted finishing coat can reduce the rate of evaporation, therefore, when this layer is present, the drying front may be located closer to the surface of the material (GONÇALVES; PEL; RODRIGUES, 2009). Among the test methodologies available to assess the drying process on building materials, it is possible to use non-destructive methods that provide an approach for moisture distribution and drying depth estimation, such as nuclear magnetic resonance (GONÇALVES; PEL; RODRIGUES, 2009) and impedance spectra (SUN et al., 2017). Nevertheless, a simple (gravimetric) evaporation test can provide information on the transport of liquid water and vapor, which can then be correlated with other physical parameters of mortars such as vapor permeability and water absorption (SCHEFFLER; PLAGGE, 2010; SOARES et al., 2014; FLORES-COLEN et al., 2016).
Abstract The Taguchi method is a powerful tool to experiment design optimiza- tion and is used in this work to optimize the cutting parameters, which reduce the chatter effect on surface quality. The present study includes feed per tooth, cutting speed, radial and axial depth of cut as control factors. An orthogonal array of L16 was used with the ANOVA analyses in order to identify the signi ﬁcant factors associated to the surface roughness and chatter vibration in three different direc- tions. The optimal cutting combination for the surface ﬁnishing was determined through the analysis of surface roughness. This are correlated with the vibrations levels recorded during the experimental tests. The study was carry-out by machining a hardened steel block with tungsten carbide coated tools. The results led to the minimum of arithmetic mean surface roughness of 1.05 µm which corre- sponded to a minimum of the mean vibration level.