Influence of extrusion cooking on physicochemical properties and starch digestion kinetics of Sphenostylis stenocarpa, Cajanus cajan, and Vigna subterranean grains

Abstract

Thermal degradation of sugars and amino acids, and depolymerization of macromolecules such as starch, proteins and fibre occasioned by high-temperature short-time extrusion cooking modify the physicochemical and functional properties of raw materials. High-temperature short-time extrusion cooking holds promise for the expanded use of non-conventional ingredients as food/feed due to its practicality, increased productivity and efficiency, and ability to retain thermally degradable nutrients during cooking. However, little is known about the effect of the high-temperature short-time extrusion cooking process on the physicochemical properties and starch digestibility of lesser-known grain legumes such as African yam beans (Sphenostylis stenocarpa), Pigeon pea (Cajanus cajan), and Bambara peanut (Vigna subterranean). In this study, we investigate the effect of high-temperature short-time extrusion cooking and extrusion cooking temperature; low (100°C) vs high (140°C) temperatures in a single screw extruder, on hydration characteristics, viscoamylolytic properties, in vitro starch digestibility and digestion kinetics of these grain legumes. We show that water holding capacity and swelling power increased (p < 0.05) with increasing extrusion temperature for Sphenostylis stenocarpa and Vigna subterranean but not Cajanus cajan extrudates. Significant effects of extrusion cooking (i.e unextruded vs 100°C and unextruded vs 140°C) and extrusion temperatures (i.e. 100°C vs 140°C) were observed in peak, trough, final and setback viscosities of all extrudates. Starch digestibility and digestion characteristics were modified with increase in extrusion temperature, however, no effect of extrusion temperatures (i.e. 100°C vs 140°C) on starch digestion kinetics was observed for Sphenostylis stenocarpa and Vigna subterranean except for hydrolysis index (34.77 vs 40.77%). Nutritional and physiological implications of extruded grain legumes in monogastric animal feeding were also highlighted. The Information presented herein will influence expanded use of extruded grain legumes as feed ingredients for intensive monogastric animal feeding.

The Exploitation of Orphan Legumes for Food, Income, and Nutrition Security in Sub-Saharan Africa

“…However, some species like AYB, BG, KG, and JB are known to contain some toxic phytochemicals that can lead to bloating, flatulence, or activate allergic reactions in some people. Fortunately, most of these toxins can be easily neutralized by steaming, de-hulling, boiling, fermenting, roasting, and using advanced processing technology such as irradiation, infrared heating (micronization), and high-pressure cooking without jeopardizing their nutritional contents ( Maphosa and Jideani, 2017 ; Adeleye et al, 2020 ; Tan et al, 2020 ; Khan et al, 2021c ). Comparative nutritional profile of raw, mature seeds, and values per 100 g of the considered orphan legumes are shown in Table 5 .…”

Effects of Different Processing Methods and Internal Components on Physicochemical Properties and Glycemic Index of Adzuki Bean Powder

“…Different eGI values could also be attributed to the presence of other components, such as polyphenols in adzuki bean powders, which have been previously described to have lower blood glucose [48]. Future studies could work on the interaction between polyphenols and starch in reducing the eGI in adzuki beans.…”

Impact of physical modifications on starch nutritional fractions: rapidly digestible starch, slowly digestible starch and resistant starch

“…Physical modifications and starch nutritional fractions to 75.3% in kidney bean, from 12.9 to 72.2% in field pea) contents were observed in kidney bean and field pea starches (Sharma et al, 2015). Extrusion increased the enzyme digestibility of African yam beans, bambara groundnut, and pigeon pea starches and increase of extrusion temperature (from 100 to 140 °C) caused further increase in the digestibility where RDS fractions were significantly increased (Adeleye et al, 2020). Increase in RDS contents after extrusion could be due to loss of structural integrity of granules as a result of increased shearing and kneading in the extruder barrel (Sharma et al, 2015).…”

“…Extrusion is a high-temperature, short-time process in which flours or starches are plasticised and cooked in a barrel under one or more varieties of conditions of moisture, pressure, temperature and mechanical shear, causing molecular transformation and chemical reactions (Adeleye et al, 2020;Riaz, 2000;Singh et al, 2007). Most of the commercially available extruders allow temperature control of the barrel and preferred levels of thermal energy input can be applied (Wolf, 2010).…”