Nilson Evelázio de Souza

Using chemometric techniques to characterize gluten-free cookies containing the whole flour of a new quinoa cultivar

Celiac disease is defined as intolerance to the gluten proteins present in certain cereals used to prepare foodstuffs. We developed and performed physico-chemical, sensory, and nutritional assessments of three formulations of gluten-free cookies containing Linum usitatissimum L. and different levels of whole Chenopodium quinoa BRS Piabiru flour. No gluten was detected in the prepared cookie formulations. The crude protein and total lipid contents ranged from 85.58 to 97.55 and 121.69 to 166.19 g per kg of sample, respectively. The polyunsaturated/saturated and n-6:n-3 fatty acid ratios ranged from 0.85:1 to 0.92:1 and 3.08:1 to 4.38:1, respectively. Formulation C had the best alpha-linolenic acid content, lipid fraction nutritional indices and mineral content per portion, with excellent sensory characteristics. Multivariate analysis highlighted the effect of the concentration of quinoa on the nutritional and sensory qualities of the product.

Method validation for simultaneous determination of cholesterol and cholesterol oxides in milk by RP-HPLC-DAD

O escopo da presente pesquisa foi desenvolver e validar uma metodologia para extracao simultânea de colesterol e oxidos de colesterol utilizando saponificacao direta em amostras de leite fluido para posterior analise por cromatografia liquida de alta eficiencia em fase reversa com deteccao por arranjo de diodos (RP-HPLC-DAD). Foram avaliados os parâmetros analiticos de seletividade, linearidade e faixa de aplicacao, precisao inter e intradia, recuperacao, limites de deteccao e quantificacao do metodo. Os resultados demonstraram que a metodologia pode ser empregada com seguranca e confiabilidade para analise do colesterol e oxidos do leite. The aim of the present work was to develop and validate a reversed-phase highperformance liquid chromatography with diode array detection (RP-HPLC-DAD) method for determination of cholesterol and cholesterol oxides extracted from milk samples. The method consisted of direct samples saponification and analytes extraction, followed by their determination using RP-HPLC-DAD. Suitable analytical selectivity, linearity and range of application, intra-assay and intermediary precision, recovery, detection and quantification limits (LOD and LOQ) were achieved and, the results showed that the developed RP-HPLC-DAD method can be applied to routine determination of cholesterol and cholesterol oxides in milk samples.

Chemometric Methods Applied to the Mineral Content Increase in Chocolate Cakes Containing Chia and Azuki

A 22 full factorial design (two factors at two levels) with duplicate was performed to investigate the influence of the percentages of chia and azuki (the two factors) added to gluten-free chocolate cake on the mineral contents (Ca, Cu, Fe, K, Mg , Mn and Zn). In the study, partially defatted chia flour and wholemeal azuki flour were used. The percentage factors of chia and azuki were significant and the increases in these values contributed positively to the responses. The interaction effect was not significant for the Ca, Fe, Mg and Zn responses. The principal component analysis (PCA) distinguished samples with higher content of chia by means of PC1, and PC2 separated the formulations with the highest levels of azuki from the ones with the lowest levels. Using analysis of variance (ANOVA) and response surface analyses, it was possible to conclude that the increase in mineral content was higher with the addition of 20% of both flours.

Effect of the addition of chia's by‐product on the composition of fatty acids in hamburgers through chemometric methods

BACKGROUND Hamburger is a meat-based food that is easy to prepare and is widely consumed. It can be enriched using different ingredients, such as chias by-product, which is rich in omega-3. Chemometrics is a very interesting tool to assess the influence of ingredients in the composition of foods. A complete factorial design 2(2) (two factors in two levels) with duplicate was performed to investigate the influence of the factors (1) concentration of textured soy proteins (TSP) and (2) concentration of chia flour partially defatted (CFPD) as a partial replacement for the bovine meat and porcine fat mix in hamburgers. RESULTS The results of proximal composition, lipid oxidation, fatty acids sums, ratios, and nutritional indexes were used to propose statistical models. The factors TSP and CFPD were significant, and the increased values contributed to improve the composition in fatty acids, crude protein, and ash. Principal components analysis distinguished the samples with a higher content of chia. In desirability analysis, the highest level of TSP and CFPD was described as the optimal region, and it was not necessary to make another experimental point. CONCLUSION The addition of chias by-product is an alternative to increase the α-linolenic contents and to obtain nutritionally balanced food.

Chemometric Study of Perilla Fatty Acids from Subcritical n-Propane Extracted Oil

O oleo de perilla (Perilla frutescens) foi extraido utilizando n-propano subcritico e tambem pela metodologia oficial de Soxhlet, para efeito de comparacao. Objetivou-se avaliar a influencia dos fatores temperatura e pressao sobre a composicao dos acidos graxos (FA), atraves de um fatorial 2 2 completo em triplicata com ponto central. Ambos os fatores analisados contribuiram significativamente para o rendimento dos FA extraidos. As superficies de resposta indicaram que o aumento da pressao e temperatura permitiu maior extracao de acidos graxos omega-3 e poli-insaturados (PUFA), e uma melhor razao entre PUFA e acido graxos saturados (SFA). Atraves da funcao de desejabilidade, a melhor condicao de extracao com n-propano foi temperatura de 80 ° C e pressao de 8 MPa. A analise multivariada distinguiu a condicao otima no grupo de maior conteudo de PUFA, com destaque para o acido alfa-linolenico, enquanto a metodologia de Soxhlet caracterizou-se com elevado teor de SFA. Oil from perilla (Perilla frutescens) was extracted using subcritical n-propane and also the Soxhlet official methodology, for comparison. This work aimed at assessing the influence of the temperature and pressure factors on the composition of fatty acids (FA), using a full 2 2 factorial design in triplicate with central point. Both factors were significant for increasing the yield of extracted FA. The response surfaces showed that increasing pressure and temperature allowed the extraction of higher levels of n-3 and polyunsaturated fatty acids (PUFA) and greater ratio values of PUFA and saturated fatty acids (SFA). According to the desirability function, the best condition of extraction using n-propane was 80 ° C for temperature and 8 MPa for pressure. In multivariate analysis the optimum condition was characterized by a higher content of PUFA, especially alphalinolenic fatty acid, while the Soxhlet methodology was characterized by high level of SFA.

Sensory and physico-chemical characteristics of desserts prepared with egg products processed by freeze and spray drying

In this work, three freeze-dried (FD) egg products (whole egg (WE), egg yolk (EY) and egg white (EW)) were obtained and the acceptability of confections prepared with each was evaluated. Sensory analyses for confections were performed by hedonic testing with fifty panelists in each evaluation. The studied confections were: Condensed Milk Pudding (P), Quindim (Q) and Meringue (M). The results obtained for confections made with FD egg products were compared with the achieved through other formulations of the same desserts made with fresh (F) or spray-dried (SD) egg products. The sensory analysis results for confections made with FD egg products showed good acceptance by panelists. A principal component analysis of the sensory evaluation data was carried out to identify similarities between the different egg products. The PCA supported the conclusion that FD egg products can substitute their fresh and SD counterparts in dessert formulations with good acceptability while keeping the advantages conferred by the freeze-drying method.

Analysis of carotenoids, α-tocopherol, sterols and phenolic compounds from white bread enriched with chia (Salvia hispanica L.) seeds and carrot (Daucus carota L.) leaves

Each food matrix is unique. Thus, the endogenous antioxidants of an underexplored bakery product might show different responses regarding free radical scavenging/resistance to forced oxidation than what is expected for other foods previously reported in the literature. In this context, a Box-Behnken design and correlation studies were applied in order to obtain more information about how specific antioxidants affect the total antioxidant activity (TAC) and the degree of forced oxidation in white breads with chia seeds and carrot leaves. Hypotheses of synergism/antagonism between the studied compounds were also elucidated in order to justify the obtained results. In this specific sample type, carotenoids and cholesterol showed the greatest relationships with results from TAC assays, as well with induction points using Oxitest® equipment, while α-tocopherol and phytosterols showed negative correlations. Phenolic compounds did not have any influence on the system because the baking procedure at high temperature had severe impacts on them.

Yield, viscosity, and gel strength of wami tilapia (Oreochromis urolepis hornorum) skin gelatin: Optimization of the extraction process

A factorial design and response surface methodology were used to optimize the extraction process of tilapia skin gelatin (Oreochromis urolepis hornorum). The concentrations of NaOH (0.15%–0.35%) and H2SO4 (0.15%–0.35%), the extraction temperature (40°C–60°C), and the extraction time (3–15 h) were independent variables. Response variables were yield (%), viscosity (mPa·s), and gel strength (g). The NaOH (%) and H2SO4 (%) concentrations had significant influences (p<0.05) on viscosity and gel strength, while the extraction temperature (°C) and the extraction time (h) showed significant influences (p<0.05) on all dependent variables. Increasing the temperature and extraction time provided higher yields with a reduction in the gelatin viscosity and gel strength. Tilapia fish skin can be used as a source for production of gelatin.

Application of box-behnken design to the study of fatty acids and antioxidant activity from enriched white bread

This work determined the proximate/fatty acid composition and the antioxidant activity of breads using a Box-Behnken design composed of fifteen experiments and three factors. The studied breads had altered baking times and the wheat flour was partially substituted by chia seeds and carrot leaves. Total antioxidant capacity results were superior to those obtained from control bread (495.33 µmol TEAC g-1 for DPPH assays and 413.85 µmol TEAC g-1 for FRAP assays), showing increased levels of 97 and 102% for DPPH and FRAP assays, respectively. The addition of chia seeds and carrot leaves led to maximal alpha-linolenic acid increase of 216.69% and maximum PUFA:SFA ratio increase of 18.88% in relation to control bread (this with alpha-linolenic acid amount of 34.03 mg g-1 total lipid and a 2.86 ratio value), as well as a maximum omega-3:omega-6 ratio reduction of 70.01% (15.59 ratio value for control bread).