Leticia Xochitl López-Martínez

Phase II-inducing, polyphenols content and antioxidant capacity of corn (Zea mays L.) from phenotypes of white, blue, red and purple colors processed into masa and tortillas.

White, blue, red and purple corns (Zea mays L.) were lime-cooked to obtain masa for tortillas. The total phenolics and anthocyanins content, antioxidant activity expressed as total reducing power (TRP), peroxyl radical bleaching (PRAC), total antioxidant activity (TAA) and quinone reductase (QR) induction in the murine hepatoma (Hepa 1 c1c7 cell line) as a biological marker for phase II detoxification enzymes were investigated. Among the extracts prepared from raw corn varieties the highest concentration of total phenolics, anthocyanins, antioxidant index and induction of QR-inducing activity were found in the Veracruz 42 (Ver 42) genotype. The nixtamalization process (masa) reduced total phenolics, anthocyanins and antioxidant activities and the ability for QR induction when was compared to raw grain. Processing masa into tortillas also negatively affected total phenolics, anthocyanin concentration, antioxidant activities, and QR induction in the colored corn varieties. The blue variety and its corresponding masa and tortillas did not induce QR. Ver 42 genotype and their products (masa and tortilla) showed the greatest antioxidant activity and capacity to induce QR

Effect of Chia Seed on Physicochemical and Sensory Characteristics of Common Carp Restructured as Functional Food

Physicochemical and sensory characteristics of restructured meat of common carp (Cyprinus carpio) fortified with 0-8 g/100 g of chia seed flour (CSF) was evaluated. It had a higher nutritional value (higher fibre content and protein retention] (p < 0.05) and better cooking characteristics (higher cooking yield and moisture retention) (p < 0.05) than the control. The colour (a*, b*) increased; lightness and whiteness index decrease (p < 0.05). Hardness increase (p < 0.05) occurred because of CSF addition. Differential scanning calorimetry showed that fibre fortification did not interfere with the thermal transitions of the restructured meat. No significant differences were detected with the preference test scores of 4% or 8% CSF compared with the control. Restructured (4%-8% CSF) had a higher content of fibre and fat, which could be linoleic and linolenic acid, and an increase in the content of protein compared with those of commercial products, among had 1.62 and 2.25 mg AGE/g. Therefore, the restructured properties of common carp were governed by CSF addition.

Evaluation of physicochemical, functional and textural properties of rainbow trout (Oncorhynchus mykiss) stored at low temperatures

The physicochemical and functional behaviour of rainbow trout stored at 4 and -20°C for nine days and six months, respectively, were investigated. The combined effect of proteolytic activity and physicochemical changes in the muscle (pH, solubility and proteolytic activity) altered the molecular structure of the proteins. SDS-PAGE showed the degradation of myosin and the formation of peptides of low molecular weight, causing an increase in solubility, which is correlated with changes in the functional properties of meat (water retention, capacity of emulsification and ability of gelling). In a gel obtained from the stored samples, the solubility had an effect on the distribution of the water gel, and significant differences (P<0.05) in colour and texture parameters were observed during storage. Regarding correlation analysis, during cooling, all variables studied were dependent on each other, however, in freezing, the correlation diminished in variables such as hardness, solubility and CRA. Surplus meat of trout according to the time of cold storage, can be incorporated into technological processes up to two days at a storage temperature of 4°C and three months at - 20°C, thus could contribute to the functional and textural properties of commercial meat products, generating a value liked trout producers. After this time of storage, the trout flesh can be consumed in the conventional way. Keywords: Rainbow trout, refrigeration, freezing, texture. African Journal of Biotechnology Vol. 12(32), pp. 5087-5096

Cooking treatments effect on bioactive compounds and antioxidant activity of quintonil (Amaranthus hybridus) harvested in spring and fall seasons

ABSTRACT This study investigated the effects of cooking treatments (boiling and steaming) and season of the year (spring and fall) on vitamin C content, total phenolics content (TPC), total flavonoids content (TFC), antioxidant activity and scavenging of nitric oxide (NO•), and superoxide radical (O2–). After cooking, a significant decrease in vitamin C was observed (50 and 48.8% for boiling and 21 and 27.9% for steaming in spring and fall, respectively). TPC and TFC increased during steaming from 145–1480 mg GAE/kg and 348.6–797.2 mg QE/kg, respectively. DPPH values ranged from 2806–3801 μmol TE/kg and was affected by season whereas ORAC ranged from 1231.3–36,167.2 μmol TE/kg and was affected by cooking. The ability to scavenge NO• and O2–, were not affected by neither cooking nor season. However, the inhibition of O2– was higher for quintonil steamed in spring.

Preparation and Evaluation of a Food Additive Based on Polymeric Nanoparticles for Controlled Delivery of Antioxidant Extracts

Background: Advances in nanotechnology have enabled new strategies for transport, controlled deliver, preservation and increases in stability of degradable biomolecules. Nanoparticles have been developed for alimentary porpoises, using a great diversity of raw materials. Poly(lactide-coglicolide) acid (PLGA) a biodegradable polyester, has been used extensively as a controlled delivery platform for a great variety of biomolecules and drugs. Methods: Extracts from Zea mays and Phaseolus vulgaris were obtained and characterized, PLGA nanoparticles were prepared by emulsion-solvent evaporation method and loaded with antioxidant extracts. Finally, antioxidant- loaded nanoparticles were incorporated into a film-forming solution and antioxidant release were tested in a meal preparation. Results: Antioxidant-loaded nanoparticles (300 – 500 nm), were prepared with adequate stability. Encapsulation efficiency showed a mean value of 67.4 % for bean and 41 % for corn extracts. IR-FT provided information about nanoparticle formation and encapsulation. Kinetic release of antioxidants demonstrate a prolonged delivery of phenolic compounds from nanoparticles (< 60 h). In situ test showed the functionality of PLGA-NP as food additive for controlled release of antioxidants. Conclusion: Antioxidant encapsulation and loading efficiency in PLGA matrix, produce a stable nanostructure with adequate characteristics for sustained and controlled release, with a great variety of possible applications as an alimentary additive.

Processing of Corn (Maize) and Compositional Features

This chapter describes the production and processing variables that influence the content of the major corn phytochemicals, namely, carotenoids and phenolics. There is substantial genetic variation in the content of each of these compounds among cultivars. The content of carotenoids and phenolics appear to be more sensitive to environmental conditions both pre- and post-harvest. Although the content of certain carotenoids and phenolics can actually increase during suitable conditions of fresh storage, phenolic compounds are more susceptible to loss during processing, especially by leaching from plant tissues into processing water (nixtamalization). Specific environmental conditions appear to increase the level of phenolic compounds but do not affect the content of carotenoids. A combination of these factors can create opportunities for the production of genotypes of corn with improved properties related to public health.