Kinetics of thermal degradation of carotenoids related to potential of mixture of wheat, cassava and sweet potato flours in baking products.

BACKGROUND: The consumption of foods such as sweet potato and cassava with high levels of carotenoids is a possible solution to reduce vitamin A deficiency. In this study, we evaluated the kinetics of thermal degradation of carotenoids. The content of carotenoids was quantified by high-performance liquid chromatography, first in fresh material, then in flour and finally in bakery products using mixtures of wheat, sweet potato and cassava. The degree of acceptance of the bakery products by children was also assessed through a sensory acceptance test. RESULTS: The study found that the degradation of carotenoid compounds in sweet potato followed first-order kinetics and fitted the Arrhenius equation with correlations of R2 > 0.9. The retention rates of all-trans-ß-carotene were 77%, 56% and 48% at cooking temperatures of 75, 85 and 95 °C respectively, during a cooking time of 20 min. The concentrations of all-trans-ß-carotene, after baking, for bread, cookies and cake were 15, 19 and 14 µg g-1 db, respectively. In a sensory acceptance test carried out in a school, 47.6% of the boys and 79.2% of the girls rated the cookies made from a mixture of cassava, sweet potato and wheat flour with the indicator I like it a lot. CONCLUSION: The content of carotenoid compounds was reduced by exposure to high temperatures and long cooking times. The combinations of cooking time and temperature which minimized degradation of all-trans-ß-carotene occurred at 75 °C-20 min and 95 °C-10 min. All-trans-ß-carotene retentions for bread, cookies and cake were 25%, 15% and 11% respectively. The mixture of wheat, sweet potato and cassava flour can be considered in the development of cookies with positive contributions of all-trans-ß-carotenes and with a good acceptance by children between 9 and 13 years old. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Characterization of cassava ORANGE proteins and their capability to increase provitamin A carotenoids accumulation.

Cassava (Manihot esculenta Crantz) biofortification with provitamin A carotenoids is an ongoing process that aims to alleviate vitamin A deficiency. The moderate content of provitamin A carotenoids achieved so far limits the contribution to providing adequate dietary vitamin A levels. Strategies to increase carotenoid content focused on genes from the carotenoids biosynthesis pathway. In recent years, special emphasis was given to ORANGE protein (OR), which promotes the accumulation of carotenoids and their stability in several plants. The aim of this work was to identify, characterize and investigate the role of OR in the biosynthesis and stabilization of carotenoids in cassava and its relationship with phytoene synthase (PSY), the rate-limiting enzyme of the carotenoids biosynthesis pathway. Gene and protein characterization of OR, expression levels, protein amounts and carotenoids levels were evaluated in roots of one white (60444) and two yellow cassava cultivars (GM5309-57 and GM3736-37). Four OR variants were found in yellow cassava roots. Although comparable expression was found for three variants, significantly higher OR protein amounts were observed in the yellow varieties. In contrast, cassava PSY1 expression was significantly higher in the yellow cultivars, but PSY protein amount did not vary. Furthermore, we evaluated whether expression of one of the variants, MeOR_X1, affected carotenoid accumulation in cassava Friable Embryogenic Callus (FEC). Overexpression of maize PSY1 alone resulted in carotenoids accumulation and induced crystal formation. Co-expression with MeOR_X1 led to greatly increase of carotenoids although PSY1 expression was high in the co-expressed FEC. Our data suggest that posttranslational mechanisms controlling OR and PSY protein stability contribute to higher carotenoid levels in yellow cassava. Moreover, we showed that cassava FEC can be used to study the efficiency of single and combinatorial gene expression in increasing the carotenoid content prior to its application for the generation of biofortified cassava with enhanced carotenoids levels.

Estudio de la bioaccesibilidad in vitro de zinc en arroz (oryza sativa) y su relación con el contenido de ácido fitico / In vitro bioaccesibility of zinc in rice (oryza sativa) and its relationship with phytic acid content

La bioaccesibilidad de un nutriente en un alimento sirve para determinar la calidad nutricional de éste para el consumo humano. El arroz es uno de los alimentos más importantes en la dieta por su gran aporte calórico y nutricional. El objetivo de este estudio fue analizar la bioaccesibilidad in vitro del zinc en arroz mediante espectrofotometría ultravioleta-visible y espectrometría de absorción atómica de llama y su relación con el contenido de ácido fítico. El porcentaje de bioaccesibilidad del zinc, respecto al porcentaje de ácido fítico, presentó una relación logarítmica inversamente proporcional (r= −0,669; p<0,05). Los valores porcentuales de bioaccesibilidad del zinc y ácido fítico en las líneas de arroz evaluadas se hallaron en un rango de 1,98,7% y 0,039-0,946% respectivamente. Se encontró que el ácido fítico afecta la bioaccesibilidad del zinc y que ésta no estuvo ligada a la concentración total del zinc presente en las líneas de arroz evaluadas. Las técnicas implementadas para cuantificar el zinc dializado presentaron diferencias significativas y se mostró que la técnica ultravioleta-visible no fue apta para este tipo de ensayos.

The bioavailability of a nutrient in a food serves to determine the nutritional quality for human consumption. Rice is one of the most important foods in diet due to its caloric and nutritional contribution. The objective of this study was to analyze the in vitro bioavailability of zinc in rice by ultraviolet-visible spectrophotometry and flame atomic absorption spectrometry and its relationship with phytic acid content. The percentage of zinc bioaccessibility with respect to phytic acid percentage, showed an inverse proportional logarithmic relationship (r= −0.669; p<0.05). The percentage values of zinc bioavailability and phytic acid in the evaluated rice varieties had a range of 1.9-8.7% and 0.039-0.946%, respectively. Phytic acid affected the bioaccessibility of zinc and was not linked to the total concentration of zinc present in the rice lines evaluated. The techniques implemented to quantify zinc dialyzed presented significant differences. It was shown that the ultraviolet-visible technique was not suitable for this type of assay.

A comparison study of five different methods to measure carotenoids in biofortified yellow cassava (Manihot esculenta).

The most commonly used method for measuring carotenoid concentration is high-performance liquid chromatography (HPLC). Nevertheless, easier, quicker, and less costly proxy methods exist. We aimed to determine the diagnostic performance of several proxy methods: the spectrophotometer, iCheck Carotene, and near-infrared spectroscopy using both a desktop (dNIRS) and a portable (pNIRS) device for the measurement of total carotenoid concentration (TCC) and all-trans-ß-carotene concentration (trans-BC) in 30 fresh cassava (Manihot esculenta Crantz) storage roots in comparison with HPLC. The spectrophotometer presented the highest predictability for TCC, followed by iCheck, dNIRS, and pNIRS. The dNIRS showed the highest predictability and agreement for trans-BC. The pNIRS showed the poorest repeatability and greatest underestimations compared with HPLC. The agreement between all methods was lower for higher carotenoid concentration, with the exception of the spectrophotometer. According to our results, and for screening purposes, the measurement of carotenoids in fresh cassava roots can be carried out by spectrophotometer, iCheck Carotene and NIRS methods depending on the availability of equipment.