RESUMO
The aim of this study is to evaluate the effect of desaponification, soaking, germination, and refrigerated storage on the phytase activity, phytic acid content, and nutritional properties of three varieties of quinoa: white, red, and black. Desaponification and soaking reduced the number of minerals and the nutritional content. Germination of the seeds was carried out in the desaponified samples. The nutritional values, phytase activity, and phytic acid content of quinoa were measured after 6 h of soaking and then at 4 and 7 days during germination plus 7 days of refrigerated storage (4 °C). Germination increased the fibre and protein content as well as the iron, zinc, and calcium content. Germination significantly increased the phytase activity in all varieties and decreased the phytic acid content. The phytic acid content decreased during germination from 32 to 74%. Refrigerated storage had no significant effect on most of the factors studied. Germination boosts nutritional content and phytase activity while decreasing phytic acid content. Germination can be a simple method to reduce phytic acid in quinoa and may also improve the nutritional quality of this pseudocereal with the potential for use in functional foods and vegetarian diets.
RESUMO
The enzymatic modification of starch extends its industrial use to flavor delivery and probiotic encapsulants, among other uses. However, it is not known how starch from different cassava varieties responds to enzymatic hydrolysis. Starches from two Ecuadorian cassava varieties (INIAP 650, an edible starch, and INIAP 651, an industrial starch) were partially modified at three enzymatic hydrolysis degrees (0%, 30%, and 50%), and their physicochemical properties were assessed. The structural analysis revealed that both varieties showed progressive structural damage as hydrolysis increases, probably due to exo-hydrolysis. However, deeper pores were observed in INIAP 651 with the SEM analysis. The crystallinity percentage obtained by XRD analyses remained constant in INIAP 651 and decreased (by 26%) in INIAP 650 (p < 0.05). In addition, the amylose−lipid complex index in INIAP 650 remained constant, while INIAP 651 increased (p < 0.05) at 30% hydrolysis (by 93%). In both varieties, hydrolysis increased (p < 0.05) the water holding capacity (WHC) (by 10−14%) and the water binding capacity (WBC) (by 16%), but 50% hydrolysis of INIAP 650 was needed to significantly affect these properties. No differences were observed in the varieties' thermal properties. Regarding the rheological properties, the variety did not influence the changes in the storage module (G') and the loss modulus (Gâ³) with the hydrolysis (p > 0.05). However, the phase angle decreased significantly (p < 0.05) with the hydrolysis, being higher in the INIAP 650 variety than in the INIAP 651 variety. In general, the results indicate that the variety affects the response of the starch granule to enzymatic hydrolysis (noticeable in the principal component analysis, PCA) and opens up the possibility to modulate starch properties.
Assuntos
Amilose , Manihot , Amilose/química , Hidrólise , Lipídeos , Manihot/química , Amido/química , Viscosidade , Água/químicaRESUMO
ABSTRACT: Bacterial foodborne diseases are among the most important public health issues worldwide, but in Ecuador, reports on the microbiological quality of food are scarce. In this cross-sectional study, 450 samples of high-demand Ecuadorian food, including bolon, encebollado, sauces, ceviche, fruit, fruit juice, fruit salad, cheese, raw chicken, and ground beef, were collected from popular street markets in the cities of Guayaquil, Quito, and Cuenca. Populations of total aerobic mesophilic bacteria, total coliforms, fecal coliforms, Escherichia coli, Salmonella enterica, and Listeria monocytogenes were examined on composited samples by plate count following the local regulations (Norma Tecnica Ecuatoriana, Instituto Ecuatoriano de Normalización) for each kind of food. The individual and interaction effects of the city and food type on the levels of each bacterial group were assessed by two-way analysis of variance. Selected colonies from each culture were identified using Biolog OmniLog ID and sequencing of the V3 to V4 region on the 16S rRNA gene. Average total aerobic mesophilic bacteria, total coliform, fecal coliform, and E. coli levels were 5.10 ± 0.12, 2.50 ± 0.16, 1.09 ± 0.12, and 0.83 ± 0.12 log CFU/g or mL, respectively, with significant variations among the cities. The prevalence of Salmonella in chicken and sauces and L. monocytogenes in cheese and fruit salad was greater than 20%. Opportunistic pathogens including Klebsiella pneumoniae, Staphylococcus sciuri, and Enterococcus spp. were frequently identified in the samples from all three cities. High prevalence of spoilage microorganisms such as Bacillus amyloliquefaciens and biocontrol bacteria such as Lactococcus lactis was also observed. This is the first report on the microbiological quality of food from Ecuador.