Resistant‐Type Starch in Sorghum Foods—Factors Involved and Health Implications

Abstract

Sorghum grain has a higher content of resistant starch (RS) than other cereals and seems to be more slowly digestible. However, people consume foods where the grain has been processed by thermal and other treatments. This review addresses whether sorghum foods generally have unusually high levels of RS and slowly digestible starch (SDS), what intrinsic factors are responsible and how processing conditions affect RS and SDS, and the health‐related implications of sorghum food consumption. With non‐tannin type sorghums, if the endosperm structure is little disrupted during food processing, as with conventional wet cooking, then the food can exert positive health effects on glycemic response related to its high RS content. Thermally induced cross‐linking of the kafirin matrix proteins appears to be responsible for the low starch digestibility. However, when non‐tannin sorghum is processed using high‐shear technologies like extrusion cooking, the endosperm, and starch granule structure are disrupted, rendering the starch fully digestible. Regarding tannin‐type sorghums, the tannins have a strong inhibitory effect on starch digestibility, notably by binding with the starch, which can improve glycemic response and other health related parameters. Future research on RS in sorghum foods must focus on the mechanisms responsible and interactions between intrinsic‐ and processing‐related factors.

Variations in Total Protein and Amino Acids in the Sequenced Sorghum Mutant Library

“…Plants 2023, 12, 1662 2 of 14 Sorghum storage proteins exhibit a strong sequence similarity to the maize storage proteins, zeins [14]; however, sorghum proteins are more hydrophobic and have a greater number of cross-linked fractions than the maize proteins, indicating their greater propensity to create intermolecular disulfide cross-connections and protein aggregates [14,15]. The combination of protein bodies and matrix protein in the endosperm forms a protein barrier around the starch granules, which in turn inhibits amylolytic enzymes from hydrolyzing native and processed starch [16,17]. Starch-gelatinizing is also negatively impacted by protein structures (protein bodies and matrix protein) [3,15].…”

A Decade of Evidence of Sorghum Potential in the Development of Novel Food Products: Insights from a Bibliometric Analysis

“…The cited authors drew attention to the fact that the syrup, which is made from the sweet-sorghum juice, has the potential to be used in developing commercial beverages since they can be further fortified or blended with other fruit juices or concentrates. They can also be with protein concentrates or other beverages, allowing for the development of products with an improved nutritional quality and with good acceptance by the nutraceutical segment due to the health benefits provided by the sorghum [10][11][12].…”

“…Over the last ten years, there has been growing interest among researchers in the health benefits of sorghum consumption [10][11][12] and the use of this grain to develop healthier food products [13][14][15]. Sorghum flour usually presents a high content of dietary fiber, fat and protein in addition to some micronutrients and several bioactive compounds that can contribute to improving the nutritional quality of cereal-based products for human consumption [11,13].…”

“…Some researchers evidence the high glycemic index of wheat-based and GF bakery products, and so, the substitution of common cereals with sorghum flour can contribute to the development of products with a lower glycemic index due to the dietary fiber and resistant starch contents of sorghum [6,12]. Also, some genotypes contain tannins in the composition, which have already shown a positive relationship with a decrease in the glycemic rate [10,18].…”

“…Due to the increasing interest in sorghum for human nutrition, recent literature reviews highlight its nutrient and bioactive content as well as its potential health benefits [6,10,12] and focus on the milling, malting, fermentation and thermal processing of sorghum to be consumed or used as a food ingredient [11]. Moreover, a current view of recent research into sorghum-based food products is needed to help both food scientists and industry identify current trends and forward-looking approaches as well as to design strategies to diminish the challenges regarding the use of sorghum for human nutrition, including the commercialization of sorghum-based food products.…”