Carotenoid composition and antioxidant activity of tortillas elaborated from pigmented maize landrace by traditional nixtamalization or lime cooking extrusion process

In Vitro Bioaccessibility of Bioactive Compounds from Rosehip-Enriched Corn Extrudates

The rosehip (Rosa canina L.) fruit has gained researchers′ attention due to its rich chemical composition in vitamin C, phenols, carotenoids, and high antioxidant activity; meanwhile, polymers such as pea protein are generally recognized as exhibiting a protection role against the extrusion process. Corn snacks extrudates obtained by replacing corn flour with 10% R. canina powder (R) and 10% R. canina with pea protein (RPP) were evaluated for the physicochemical, textural, optical, and nutritional characteristics. A sample manufactured without R. canina powder was used as a control. Hardness, crispiness, chewiness, and solubility index (WSI) of the final extrudates were improved by addition of R. canina and pea protein powder (PP); meanwhile, b* (yellow/blue coordinate), C (chroma), and h* (tone) optical parameters were significantly different from the control sample (p < 0.05). Extrusion highlighted a negative impact on total phenols, carotenoids, vitamin C, and antioxidant activity extrudates, while PP exhibited a good protection against the extrusion process. In vitro digestion increased the bioaccessibility of vitamin C, folate, antioxidant activity, total phenols, and total carotenoids mainly on RPP extrudates.

Colored Corn: An Up-Date on Metabolites Extraction, Health Implication, and Potential Use

Colored (orange, pink, red, purple, and blue) corn strongly attracted attention on its healthy properties mainly due to its anthocyanin and carotenoid composition which is also responsible for its pigmentation. The present review summarized the recent updates on the extraction and chemical characterization of the main plant secondary metabolites present in colored seeds, kernel, cob, husk, and silk. The main approaches used to stabilize the extracts have been discussed as well as their food and non-food uses. Both in vitro and in vivo (animal models) studies on the different effects (antibacterial, antimutagenic, antioxidant, and anti-inflammatory activities, effects on metabolic syndrome, diabetes, glucose and lipidic metabolism, and neuroprotection) of pigmented extracts on animal and human health have been summarized.

Effects of three cooking methods on content changes and absorption efficiencies of carotenoids in maize

Maize is a staple source of certain carotenoids for the human diet, but food processing is an important factor affecting the carotenoid content and absorption. In this study, we investigated the content changes of carotenoids in maize under three cooking methods (boiling kernels, preparing porridge and preparing tortilla). Also, using the in vitro digestion model, we assessed the effects of the cooking methods on carotenoid absorption efficiencies (digestion stability, micellization efficiency and bioaccessibility). The results indicated that the carotenoid content obviously increased in the boiled kernels, but its carotenoid bioaccessibility was the lowest compared to that of porridge and tortilla. Tortilla presented the highest digestion stability of β-carotene (309 ± 63%) and bioaccessibility of xanthophylls (22.4 ± 0.5% for lutein and 18.5 ± 1.0% for zeaxanthin) among the three cooked products during in vitro digestion. The contents of carotenoids in the porridge were all the lowest among the three cooked products; however, the low concentration level of xanthophylls reduced the competitive effect on β-carotene micellization, which increased the bioaccessibility of β-carotene to 52.1 ± 5.0%. Additionally, the content of xanthophylls (lutein + zeaxanthin) in digesta significantly and positively correlated with the β-carotene content in digesta, whereas it negatively correlated with the micellization of β-carotene. This correlation between the xanthophylls and β-carotene was not affected by the cooking methods. These results together suggest that tortilla and porridge are better dietary choices for the intake of xanthophylls and β-carotene, respectively, among maize-based foods. Furthermore, the absorption of β-carotene was influenced by the content of xanthophylls whatever the cooking method.

The Application of Metabolomics for the Study of Cereal Corn (Zea mays L.)

Corn (Zea mays L.) is an important cereal crop indigenous to the Americas, where its genetic biodiversity is still preserved, especially among native populations from Mesoamerica and South America. The use of metabolomics in corn has mainly focused on understanding the potential differences of corn metabolomes under different biotic and abiotic stresses or to evaluate the influence of genetic and environmental factors. The increase of diet-linked non-communicable diseases has increased the interest to optimize the content of bioactive secondary metabolites in current corn breeding programs to produce novel functional foods. This review provides perspectives on the role of metabolomics in the characterization of health-relevant metabolites in corn biodiversity and emphasizes the integration of metabolomics in breeding strategies targeting the enrichment of phenolic bioactive metabolites such as anthocyanins in corn kernels.

Comparison of nutritional properties and bioactive compounds between industrial and artisan fresh tortillas from maize landraces

Consumers are seeking for native-traditional foods to improve their intake of both nutrients and health-promoting phytochemicals. This study was designed to evaluate the difference in content of nutrients and bioactive compounds from handmade tortillas elaborated by a small-scale artisan producer and tortillas sold by a large food retailer available to consumers. All tortillas were analyzed for chemical composition, dietary fiber, calcium and phytochemical content, antioxidant capacity, and phenolic acids profile. Chemical and nutritional variation in the tortillas was estimated using principal component analysis. Data showed that artisan tortillas made from blue and white maize landraces had significantly (p < 0.05) higher content of nutritional and bioactive compounds compared to those of the supermarket. Handmade blue maize tortillas (HBMT) had a high content of free phenolics content and the highest antioxidant capacity (DPPH and ABTS methods), which was around 1.7–2.1 fold higher than that of commercially produced white maize tortillas (CWMT). Total dietary fiber was higher in HBMT (15.7 ± 1.06 g/100 g) than in CWMT (11.6 ± 0.96 g/100 g). CWMT had the lowest calcium content (42.1 ± 0.9 mg/100 g) compared to handmade tortillas (155.5 ± 4.5 mg/100 g). HPLC results indicated the presence of ferulic, p-coumaric, caffeic, syringic and 4-hydroxybenzoic acids. Interestingly, handmade tortillas from blue maize had 4.5-fold ferulic acid content compared with commercially produced white maize tortillas, consequently it can be a good source of phenolic antioxidants, particularly ferulic acid. This study showed that artisan fresh tortillas had superior nutritional-nutraceutical properties compared to CWMT.

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Blue tortillas (BT) are a source of nutrients and health-promoting phytochemicals.

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BT possessed the highest content of dietary fiber, phenolic acids, and anthocyanins.

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BT had 4.5-fold high ferulic acid compared with commercial white maize tortillas.

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Importance of tortillas food data generated on people nutrition has been highlighted.

Extrusion and nixtamalization conditions influence the magnitude of change in the nutrients and bioactive components of cereals and legumes

Cereal and legume diets make up the bulk of caloric sources for a majority of households in the developing world. They contain macro- and micronutrients as well as phytochemicals embedded as one matrix. Some phytochemicals are antinutritional factors which can bind nutrients thereby hindering their bioavailability. While there are other methods that can be used to enhance nutrient utilization from such foods, we summarize how food processing methods such as extrusion and nixtamalization are employed to break the food matrix and release these nutrients. Both extrusion and nixtamalization can break down complex carbohydrates into simpler, more soluble forms while at the same time inactivating or denaturing protein inhibitors and other antinutritional factors. Such disruptions of complexes within the food matrix are essential for harnessing optimum nutritional and health benefit from these foods. We present mechanistic approaches explaining how these processes enhance nutrient and mineral bioavailability and phytochemical bioactivity while minimizing the undesirable effects of antinutritional factors that coexist in the complex food matrix.

Changes in the functional components and radical scavenging activity of maize under various roasting conditions

The phenolic compounds and radical scavenging activity of ethanolic extracts from maize at various roasting conditions were evaluated in this research. The free sugar contents in roasted maize significantly decreased with higher roasting temperature and longer roasting time. The total polyphenol and total flavonoid contents in roasted maize significantly increased with higher roasting temperature and longer roasting time. The predominant phenolic acid in the roasted maize was homogentisic acid. The contents of homogentisic acid and myricetin in roasted maize significantly increased with higher roasting temperature and longer roasting time. The DPPH and ABTS radical scavenging activities of roasted maize significantly increased with higher roasting temperature and longer roasting time. DPPH and ABTS radical scavenging activities were positively correlated with phenolic compounds. The activities of these components increased following heat treatments because of the low molecularization effects of the heating process, which resulted in active, low-molecular-weight components that were readily extracted.

Carotenoid Stability during Dry Milling, Storage, and Extrusion Processing of Biofortified Maize Genotypes

Translation of the breeding efforts designed to biofortify maize ( Z. mays) genotypes with higher levels of provitamin A carotenoid (pVAC) content for sub-Saharan Africa is dependent in part on the stability of carotenoids during postharvest through industrial and in-home food processing operations. The purpose of this study was to simulate production of commercial milled products by determining the impact of dry milling and extrusion processing on carotenoid stability in three higher pVAC maize genotypes (C17xDE3, Orange ISO, Hi27xCML328). Pericarp and germ removal of biofortified maize kernels resulted in ∼10% loss of total carotenoids. Separating out the maize flour fraction (<212 μm) resulted in an additional ∼15% loss of total carotenoids. Carotenoid degradation was similar across milled maize fractions. Dry-milled products of Orange ISO and Hi27xCML328 genotypes showed ∼28% pVAC loss after 90-days storage. Genotype C17xDE3, with highest levels of all- trans-β-carotene, showed a 68% pVAC loss after 90-day storage. Extrusion processing conditions were optimal at 35% extrusion moisture, producing fully cooked instant maize flours with high pVAC retention (70-93%). These results support the notion that postharvest losses in maize milled fractions may be dependent, in part, on genotype and that extrusion processing may provide an option for preserving biofortified maize products.

Phenolic Acids Profiles and Cellular Antioxidant Activity in Tortillas Produced from Mexican Maize Landrace Processed by Nixtamalization and Lime Extrusion Cooking

Phenolic acids profiles, chemical antioxidant activities (ABTS and ORAC), as well as cellular antioxidant activity (CAA) of tortilla of Mexican native maize landraces elaborated from nixtamalization and lime cooking extrusion processes were studied. Both cooking procedures decreased total phenolics, chemicals antioxidant activity when compared to raw grains. Extruded tortillas retained 79.6-83.5%, 74.1-77.6% and 79.8-80.5% of total phenolics, ABTS and ORAC values, respectively, compared to 47.8-49.8%, 41.3-42.3% and 43.7-44.4% assayed in traditional tortillas, respectively. Approximately 72.5-88.2% of ferulic acid in raw grains and their tortillas were in the bound form. Regarding of the CAA initially found in raw grains, the retained percentage for traditional and extruded tortillas ranged from 47.4 to 48.7% and 72.8 to 77.5%, respectively. These results suggest that Mexican maize landrace used in this study could be considered for the elaboration of nixtamalized and extruded food products with nutraceutical potential.

Effect of Traditional and Extrusion Nixtamalization on Carotenoid Retention in Tortillas Made from Provitamin A Biofortified Maize (Zea mays L.)

Provitamin A (proVA) enhanced maize was developed to help alleviate vitamin A deficiency in maize-consuming populations. Nixtamalization (lime-cooking process) is the most commonly used maize-preparation method in Mexico and Central America. In this study, the effect of traditional nixtamalization (TN) and nixtamalized extrusion (NE) on proVA retention was evaluated. Kernel conversion to TN dough led to high proVA apparent retention (>100%), while kernel conversion to NE flour led to lower retention (85%). However, TN tortilla proVA carotenoid concentration was similar to the kernels' original concentration and slightly higher in NE tortillas. Genotypic variation has a strong effect on proVA retention in TN dough and NE flour, but no such variation in proVA retention was observed in tortillas. Tortillas prepared with proVA-enhanced maize, using either TN or NE, are a good source of proVA carotenoids. Also, dough made using TN and proVA-enhanced maize is a high proVA-content ingredient for other food products.