Physicochemical properties of nixtamalized corn flours with and without germ

Flavor and TASTE attributes and nutritional insights of maize tortillas from landraces of Mexican races

Maize tortilla is the best-recognized food product of Mexican gastronomy. Artisanal maize tortillas (AMT) are prepared with native maize varieties and a traditional process. The aims of this study were to identify sensory attributes, texture, and color in AMT that allow them to be differentiated from commercial tortillas, and to determine the chemical and mineral composition of both types of tortillas. Six landraces related to four Mexican maize races were used. Two commercial tortillas were included as references (tortillería and supermarket). Tortillas were subjected to sensory analysis by the modified Flash technique, texture and color were measured objectively and chemical and mineral analysis of all tortillas were evaluated. Lime taste and lime smell attributes were relevant to differentiate AMT from commercial tortillas; aftertaste and fracturability attributes were highly associated to supermarket tortillas. The fracturability attribute of tortillas is consider undesirable for taco preparation. Five of the six AMT were characterized by the presence of a layer, a characteristic that is associated with traditional tortilla made by Mexican consumer. Regarding chemical composition, supermarket tortillas exhibited the highest dietary fiber content (17.09%), but showed 30% more Na than AMT, with the exception of tortillas from Purepecha native variety. Besides, supermarket tortilla had 48.9% less Ca than AMT. The sensory attributes relevant to differentiate native maize tortillas from the commercial maize tortilla references were appearance, smell, and taste, while textural and color attributes played a lesser role.

A comprehensive review of cereal germ and its lipids: Chemical composition, multi-objective process and functional application

Cereal germ (CG), a by-product of grain milling, has drawn much attention in the food industry because of its nutritional and functional advantages. Nowadays, the utilization of cereal germ from animal feeds to foodstuff is a popular trend. CGs have high content of polyunsaturated fatty acids in their lipids (43.9-64.9% of total fatty acids), but they are also induced to oxidative rancidity under the catalytic reaction of enzymes. Chemical and structural properties of lipids in CGs are affected by different treatments. Thermal and non-thermal effects prevent lipid oxidation or promote lipid combination with starch/protein in CG. Thus, the functional properties and final quality of CG are directly changed. In this review, the chemical composition and application of CGs especially the endogenous lipids are summarized and the effects of various processes on CG lipids/matrices are discussed for CG future development.

Kernel characterization and starch morphology in five varieties of Peruvian Andean maize

Peruvian Andean maize (PAM) has been commonly used as an ingredient that confers color, flavor, and texture in culinary. Nevertheless, no studies are focusing on agro-industrial interest characteristics to develop new products. This study aimed to evaluate the physicochemical, nutritional, and technological characteristics of kernels and the starch granule morphology of the five main PAM varieties: Chullpi, Piscorunto, Giant Cuzco, Sacsa, and Purple. PAM's characterization was performed according to the official methods, and its morphology was observed by scanning electron microscopy (SEM). Physically, the varieties of larger kernels (Giant Cuzco and Sacsa) presented a higher 1000-kernel weight and a lower hectoliter weight than those of smaller size (Piscorunto, Purple, and Chullpi). Nutritionally, PAM had higher ether extract (5%) and ash (2%) contents than other pigmented maizes. Likewise, they presented more significant amounts of essential amino acids, as leucine (10 mg/g protein) and tryptophan (up to 2 mg/g protein); unsaturated fatty acids, oleic (30%) and linoleic (53%); and minerals, as magnesium (104 mg/100 g). SEM showed that endosperm structure and starch morphology vary according to maize types and their grain location. Starch granules of floury PAM varieties were small and polyhedral in the sub-aleurone endosperm, whereas those of the central area were bigger and spherical. In Chullpi, it was observed a portion of vitreous endosperm with a compact structure. The low protein content (8.3%) and the endosperm structure of floury varieties of PAM influenced their pasting properties. Their pasting temperature was <69 to 71 °C>, peak viscosity < 3200 to 4400 cP>, and seatback <1250 to 1706 cP>; therefore, they do not retrograde easily. The results suggest that PAM has characteristics that would help elaborate regional products with added value, such as soups, willows, beverages, and porridges.

Physicochemical Properties and Resistant Starch Content of Corn Tortilla Flours Refrigerated at Different Storage Times

The tortilla is a foodstuff that has a short shelf-life, causing great losses to the industry. The objective of this work was to evaluate, for the first time, the physicochemical properties and resistant starch (RS) content of flours. These were obtained from nixtamalized corn tortillas made with traditional and industrial (commercial) methods, stored at 4 °C for 7, 15, and 30 days. The flours were characterized by measuring particle size distribution, color, water absorption index (WAI), water solubility index (WSI), viscosity, calcium, and RS content. Additionally, chemical proximate analysis, scanning electron microscopy (SEM), and thermal analysis were conducted. Storage at 4 °C increased the friability of tortillas and shifted the particle size distribution toward a greater content of coarse particles in corn tortilla flours. The commercial corn tortilla flours showed higher WAI and WSI values than the traditional corn tortilla flours. On the other hand, the traditional corn tortilla flours exhibited higher RS content values than commercial corn tortilla flours as well as peak viscosity. X-ray diffractograms revealed the presence of amylose-lipid complexes (RS5) in experimental samples. The thermograms evidenced three endotherms corresponding to corn starch gelatinization and melting of type I and type II amylose-lipid complexes.