Optimization of ultrasound-assisted extraction of sorghum phenolics and effect on the stability of 3-deoxyanthocyanins.

Sorghum 3-deoxyanthocyanins (3-DXAs) have greater stability when compared to other anthocyanins. However, the efficiency in extracting these phenolic compounds from cereals, using conventional methods, is low, because most of them are bound to the cell wall. Thus, the aim of this study was to optimize the ultrasound-assisted extraction (UAE) of anthocyanins and total phenolics from sorghum flour, and evaluate the stability of the 3-DXAs. Two frequencies (25 and 45 kHz) were applied in a Central Composite Rotational design to investigate the effect of the variables time (5-75 min) and temperature (30-65°C) using the UAE, with amplitude of the ultrasonic power set at 400 W. In addition, the stability of the 3-DXAs present in the extracts was evaluated. It was possible to successfully optimize the extraction of total anthocyanins (both frequencies) and phenolics (at 45 kHz), and then to obtain equations, to predict their concentrations, with high R2 . The efficiency of UAE was observed, increasing the yield of total anthocyanins, phenolics, and antioxidant capacity at the frequencies of 25 and 45 kHz by 30% and 27%, 10% and 5%, and 30% and 15%, respectively. The apigeninidin was the major 3-DXA found in the extracts, and the luteolinidin was the most stable over storage time. Overall, there was no difference in the 3-DXAs stability obtained by the UAE compared to the conventional method. Thus, ultrasound is an alternative to obtaining sorghum extracts rich in 3-DXAs and other phenolic compounds. PRACTICAL APPLICATION: The health benefits of sorghum 3-deoxyanthocyanins coupled with the growing interest of the food industry in producing healthier food products have motivated this study, because it is important to find ways to optimize 3-deoxyanthocyanins extraction. We have demonstrated that ultrasound-assisted extraction was efficient in extracting high amounts of 3-deoxyanthocyanins and other phenolics from sorghum flour. Moreover, some 3-deoxyanthocyanins have shown to be more stable than others after extraction. Thus, the ultrasound has great potential to produce sorghum phenolic extracts rich in 3-deoxyanthocyanins, which can be used as natural colorants and functional ingredients in foods.

Peach Palm By-Product Bioconversion by Shiitake Culinary-Medicinal Mushroom Lentinula edodes (Agaricomycetes) for Food Products Application in Brazil.

This study aims to analyze the peach palm by-product (shells) bioconversion by culinary-medicinal mushroom Lentinula edodes to obtain a food ingredient for dietary supplementation containing high contents of dietary fiber, protein, and ß-glucans. The ß-glucans production by L. edodes mycelium was optimized through a solid-state fermentation, checking the influence of the heart of palm shells and supplements (rice bran, manioc flour, and sorghum flour) through an experimental mixing plan. The cultivation treatment that presented the highest tendency for ß-glucans production was analyzed by the centesimal composition and in vivo biological activity. Treatments 4 (with shells, rice bran, and manioc flour) and 6 (with shells, sorghum flour, and manioc flour) presented the highest ß-glucans content. A flour was obtained with high dietary fiber and protein content, and low lipids and carbohydrates content, and low caloric value. The in vivo biological activity demonstrated high protein quality and promoted a lower elevation of the glycemic curve. Thus, technology for the transformation of peach palm shells into a food ingredient was made feasible. It could generate a gluten-free and lactose-free dietary supplement that is both nutritive and bioactive, enhancing human health and well-being as well as environmental sustainability.

Iron bioavailability of different maize genotypes developed in a breeding program: in vitro and in vivo studies

The objective of this study was to evaluate iron bioavailability of maize genotypes, and analyze the correlation between in vitro and in vivo methods. Dialysable iron was analyzed in 13 genotypes from which 5 were selected for the biological assay. Mean iron content of the genotypes (n=13) was 17.93±2.93 mg kg-1. Phytate varied from 0.77% to 1.03%; phytate: iron molar ratio from 30.64 to 55.41; and soluble iron from 13.17 to 39.63%. The highest value for dialysable iron was 19.14%. In the biological assay, the control group, that received ferrous sulphate, did not present significant difference between the genotypes for Hb gain, Hb gain per gram of iron consumed and HRE. Hb gain did not present a significant correlation with in vitro assay. However, there were positive correlations varying from 0.653 to 0.809. The maize genotypes evaluated presented a good bioavailability since the genotypes showed the same result in hemoglobin gain than control group.

Biodisponibilidade de ferro de diferentes genótipos de milho desenvolvidos em programa de melhoramento genético: estudos in vitro e in vivo. O objetivo deste estudo foi avaliar a biodisponibilidade do ferro de genótipos de milho e analisar a correlação entre métodos in vitro e in vivo. Ferro dialisável foi analisado em13 genótipos, a partir do qual 5 foram selecionados para o ensaio biológico. A média de teor de ferro dos genótipos (n= 13) foi 17,93 ± 2,93 mg kg-1. O teor de fitato variou de 0,77% a 1,03%; razão molar fitato:ferro de 30,64 a 55,41; e ferro solúvel de 13,17 a 39,63%.O valor mais alto para o ferro dialisável foi 19,14%. No ensaio biológico, o grupo controle, que recebeu sulfato ferrso, não apresentou diferença significativa entre os genótipos no ganho Hb, ganho de Hb por grama de ferro consumido e HRE. Ganho de Hb não apresentou correlação significativa com o ensaio in vitro. No entanto, houve correlações positivas variando de 0,653 a 0,809. Os genótipos de milho avaliados apresentaram uma boa biodisponibilidade uma vez que os genótipos apresentaram o mesmo resultado quanto ao ganho de hemoglobina em relação ao grupo controle.

Iron bioavailability of different maize genotypes developed in a breeding program: in vitro and in vivo studies.

The objective of this study was to evaluate iron bioavailability of maize genotypes, and analyze the correlation between in vitro and in vivo methods. Dialysable iron was analyzed in 13 genotypes from which 5 were selected for the biological assay. Mean iron content of the genotypes (n = 13) was 17.93 +/- 2.93 mg kg(-1). Phytate varied from 0.77% to 1.03%; phytate: iron molar ratio from 30.64 to 55.41; and soluble iron from 13.17 to 39.63%. The highest value for dialysable iron was 19.14%. In the biological assay, the control group, that received ferrous sulphate, did not present significant difference between the genotypes for Hb gain, Hb gain per gram of iron consumed and HRE. Hb gain did not present a significant correlation with in vitro assay. However, there were positive correlations varying from 0.653 to 0.809. The maize genotypes evaluated presented a good bioavailability since the genotypes showed the same result in hemoglobin gain than control group.