In this review, recent reports on in vitro starch hydrolysis kinetics are reviewed with regard to the structural characteristics of starches. Factors such as starch granule morphology, amylose to amylopectin ratio, molecular structure, degree of branching in terms of steric hindrance and consequently mass transfer resistance and their effects on the digestibility and absorption of digested carbohydrates have been examined. The physical state of the starch ingested has a major impact on the digestibility therefore effects of processing techniques (thermal processing, extrusion cooking, autoclaving etc.) and starch modification have been discussed. The other constituents of the food matrix, such as proteins, lipids and polysaccharides, play a significant role during processing which affects the physico-chemical characteristics of digesta and the final digestibility of starch. Some molecules naturally occurring in food sources may confer an inhibitory effect during starch hydrolysis.

Starch digestibility in food matrix: a review

Sorghum is the fifth most produced cereal in the world and is a source of nutrients and bioactive compounds for the human diet. We summarize the recent findings concerning the nutrients and bioactive compounds of sorghum and its potential impact on human health, analyzing the limitations and positive points of the studies and proposing directions for future research. Sorghum is basically composed of starch, which is more slowly digested than that of other cereals, has low digestibility proteins and unsaturated lipids, and is a source of some minerals and vitamins. Furthermore, most sorghum varieties are rich in phenolic compounds, especially 3-deoxyanthocyanidins and tannins. The results obtained in vitro and in animals have shown that phenolics compounds and fat soluble compounds (polycosanols) isolated from sorghum benefit the gut microbiota and parameters related to obesity, oxidative stress, inflammation, diabetes, dyslipidemia, cancer, and hypertension. The effects of whole sorghum and its fractions on human health need to be evaluated. In conclusion, sorghum is a source of nutrients and bioactive compounds, especially 3-deoxyanthocyanidins, tannins, and polycosanols, which beneficially modulate, in vitro and in animals, parameters related to noncommunicable diseases. Studies should be conducted to evaluate the effects of different processing on protein and starch digestibility of sorghum as well as on the profile and bioavailability of its bioactive compounds, especially 3-deoxyanthocyanidins and tannins. Furthermore, the benefits resulting from the interaction of bioactive compounds in sorghum and human microbiota should be studied.

Sorghum (Sorghum bicolor L.): Nutrients, bioactive compounds, and potential impact on human health.

Research involving resistant starch (RS) is becoming more prominent. RS has the ability to modulate postprandial blood-glucose levels and can be fermented by the colonic microflora to produce short-chain fatty acids, which exert positive health benefits on the consumer such as increased colonic blood flow to ease colonic inflammation and a decreased risk of colon and/or other cancers. This paper reviews the effects of genetic manipulation on amylose levels in plants, enzymatic hydrolysis, physical treatments, chemical modifications, exposure to γ-rays, and the effects of lipid complexation on the RS content of starches from various botanical sources. All treatments reviewed increased the RS content; however, select treatments (namely genetic manipulation, enzymatic debranching, hydrothermal treatments, high hydrostatic pressure, most chemical modifications, γ-irradiation exposure, as well as lipid complexation) were more effective to varying degrees than were extrusion and mineral acid treatments. Various methods commonly used for measuring RS were compared. Additionally, the effects of food matrix components were also examined to gauge their effectiveness at inhibiting or enhancing RS formation, with lipids and gums known to be the most effective at enhancing (or apparently enhancing) RS. This review draws largely, but not exclusively, from research published post 2009.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/1541-4337.12104

Methodologies for Increasing the Resistant Starch Content of Food Starches: A Review

Digestibility of protein and starch from sorghum (Sorghum bicolor) is linked to biochemical and structural features of grain endosperm

Study on starch-protein interactions and their effects on physicochemical and digestible properties of the blends.

To understand the influence of the sorghum and maize endosperm protein matrix honeycomb structure on starch hydrolysis in flours, three-dimensional fluorescence microscopy was applied to floury and vitreous endosperm flours cooked under various conditions. Cooking caused the collapse and matting of the sorghum and maize vitreous endosperm matrices, with the effect being greater in sorghum. The effect of cooking was rather different in the floury endosperm in that the protein matrices expanded and broke up to some extent. These effects were a consequence of expansion of the starch granules through water uptake during gelatinization. Cooking in the presence of 2-mercaptoethanol caused an expansion of the vitreous endosperm matrix mesh due to breakage of disulfide bonds in the protein matrix. Mercaptoethanol also caused an increase in the proportion of β-sheet structure relative to α-helical structure of the endosperm proteins. Increased energy of cooking caused collapse of the sorghum matrix. Disul...

Influence of Cooking Conditions on the Protein Matrix of Sorghum and Maize Endosperm Flours

https://repository.up.ac.za/bitstream/handle/2263/19722/Amonsou_Highly(2012).pdf?sequence=1

K. Gyebi Duodu

Papers

Influence of Cooking Conditions on the Protein Matrix of Sorghum and Maize Endosperm Flours

Highly viscous dough-forming properties of marama protein.