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Food-to-food fortification (FtFF) with moringa leaf (iron source) and/or baobab fruit (citric acid and ascorbic acid source) (each 13–15 g/100 g porridge dry basis (db)) was studied to improve iron and zinc nutritive quality in African-type wholegrain maize-based porridges using in vitro dialysability assay. Moringa FtFF decreased percentage and total bioaccessible iron and zinc, by up to 84% and 45%, respectively. Moringa was very high in calcium, approximately 3% db and calcium–iron–phytate complexes inhibit iron bioavailability. Baobab FtFF increased percentage and total bioaccessible iron and zinc, especially in porridges containing carrot + mango (β-carotene source) and conventionally fortified with FeSO4, by up to 111% and 60%, respectively. The effects were similar to those when ascorbic and citric acids were added as mineral absorption enhancers. While moringa FtFF could be inhibitory to iron and zinc bioavailability in cereal-based porridges, baobab fruit FtFF could improve their bioavailability, especially in combination with conventional iron fortification. [ABSTRACT FROM AUTHOR]

Endosperm lysine content is genetically variable in maize (Zea mays L.) germplasm, but its level is below the minimum dietary standard set by the FAO. Increasing the content of this essential amino acid in endosperm proteins depends on understanding the mechanisms regulating the synthesis and accumulation of lysine-rich proteins. In this study, we analyzed the variability for lysine and protein contents in maize endosperm. Amounts of total protein, zeins, and non-zeins measured by microKjeldahl, and lysine content, estimated by amino-acid analysis, were determined for 93 maize inbreds. Additionally, an ELISA was used to estimate the relative content of the protein synthesis factor EF-1[Alpha] in 20 selected genotypes. Considerable differences in lysine content were observed among normal and opaque2 genotypes, with the effect of the mutation being highly dependent on the genetic background. We detected a high correlation between the lysine content and the concentration of total non-zein proteins and EF-1[Alpha]. An assay for EF-1[Alpha] concentration may provide a simple and inexpensive method from breeding programs to select for improved protein quality.

In a previous trial in Mali, we showed that traditional pearl millet couscous and thick porridge delayed gastric emptying (about 5 h half-emptying times) in a normal-weight population compared with non-traditional carbohydrate-based foods (pasta, potatoes, white rice; about 3 h half-emptying times), and in a gastric simulator we showed millet couscous had slower digestion than wheat couscous. In light of these findings, we tested the hypothesis in a normal-weight US population (n 14) that millet foods would reduce glycaemic response (continuous glucose monitor), improve appetitive sensations (visual analogue scale ratings), as well as reduce gastric emptying rate (13C-octanoic acid breath test). Five carbohydrate-based foods (millet couscous – commercial and self-made, millet thick porridge, wheat couscous, white rice) were fed in a crossover trial matched on available carbohydrate basis. Significantly lower overall glycaemic response was observed for all millet-based foods and wheat couscous compared with white rice (P ≤ 0·05). Millet couscous (self-made) had significantly higher glycaemic response than millet couscous (commercial) and wheat couscous (P < 0·0001), but as there were no differences in peak glucose values an extended glycaemic response was indicated for self-made couscous. Millet couscous (self-made) had significantly lower hunger ratings and higher fullness ratings (P < 0·05) than white rice, millet thick porridge and millet couscous (commercial). A normal gastric emptying rate (<3 h half-emptying times) was observed for all foods, with no significant differences among them. In conclusion, some traditionally prepared pearl millet foods show the potential to reduce glycaemic response and promote satiety. [ABSTRACT FROM AUTHOR]

A high level of correlation exists between the lysine content of the maize endosperm and the elongation factor 1-alpha (EF1-alpha) concentration which indicates the importance of proper genetic selection for better nutritional quality. The opaque2 mutation increases the lysine content two-fold and overexpression of EF1-alpha is observed in the endosperm. The lysine contents of sorghum and barley also show similar behavior.

Summary: Isomaltodextrin (IMD) is a novel highly branched α‐glucan with emerging applications in foods due to its nutritional functionalities. In this study, the impact of IMD on the viscoelasticity and microstructure of starch gels and starch retrogradation were investigated. IMD solutions displayed typical Newtonian behaviour. Their viscosities had a positive correlation with concentration and a negative correlation with temperature. When maintained at relative humidity of 95%, IMD absorbed 40% water of its original weight. The addition of IMD to normal corn starch increased strength of gels as indicated by higher storage moduli (G′) and resulted in a denser and smaller pore structure, but there were no changes in elasticity. Upon storage for 7 days, addition of IMD at high concentration (starch: IMD = 2:1) significantly increased the degree of starch retrogradation. This study provided perspectives underlying applications of IMD in starchy foods as a novel ingredient with textural functionality. [ABSTRACT FROM AUTHOR]

The glycemic carbohydrates we consume are currently viewed in an unfavorable light in both the consumer and medical research worlds. In significant part, these carbohydrates, mainly starch and sucrose, are looked upon negatively due to their rapid and abrupt glucose delivery to the body which causes a high glycemic response. However, dietary carbohydrates which are digested and release glucose in a slow manner are recognized as providing health benefits. Slow digestion of glycemic carbohydrates can be caused by several factors, including food matrix effect which impedes α-amylase access to substrate, or partial inhibition by plant secondary metabolites such as phenolic compounds. Differences in digestion rate of these carbohydrates may also be due to their specific structures (e.g. variations in degree of branching and/or glycosidic linkages present). In recent years, much has been learned about the synthesis and digestion kinetics of novel α-glucans (i.e. small oligosaccharides or larger polysaccharides based on glucose units linked in different positions by α-bonds). It is the synthesis and digestion of such structures that is the subject of this review. [ABSTRACT FROM AUTHOR]