Combined Effects of Calcium Addition and Thermal Processing on the Texture and In Vitro Digestibility of Starch and Protein of Black Beans (Phaseolus vulgaris)

Abstract

Legumes are typically soaked overnight to reduce antinutrients and then cooked prior to consumption. However, thermal processing can cause over-softening of legumes. This study aimed to determine the effect of calcium addition (0, 100, 300, and 500 ppm in the form of calcium chloride, CaCl2), starting from the overnight soaking step, in reducing the loss of firmness of black beans during thermal processing for up to 2 h. The impact of calcium addition on the in vitro starch and protein digestibility of cooked beans was also assessed. Two strategies of calcium addition were employed in this study: (Strategy 1/S1) beans were soaked and then cooked in the same CaCl2 solution, or (Strategy 2/S2) cooked in a freshly prepared CaCl2 solution after the calcium-containing soaking medium was discarded. Despite the texture degradation of black beans brought about by increasing the cooking time, texture profile analysis (TPA) revealed that their hardness, cohesiveness, springiness, chewiness, and resilience improved significantly (p < 0.05) with increasing calcium concentration. Interestingly, beans cooked for 2 h with 300 ppm CaCl2 shared similar hardness with beans cooked for 1 h without calcium addition. Starch and protein digestibility of calcium-treated beans generally improved with prolonged cooking. However, calcium-treated beans cooked for 1 h under S2 achieved a reduced texture loss and a lower starch digestibility than those beans treated in S1. A lower starch digestion could be desired as this reflects a slow rise in blood glucose levels. Findings from this result also showed that treating black beans with high level of CaCl2 (i.e., 500 ppm) was not necessary, otherwise this would limit protein digestibility of cooked black beans.

Effect and mechanism of glycerol monostearate dimer (GMS‐D) and baking‐treatment on the structure, in vitro digestion of gelatinized potato starch‐GMS‐D

“…Although the low GI of GPS‐GMS‐D was determined, the flavor of GPS‐GMS‐D was supposed to be enhanced with appropriate and moderate post‐thermal processing (Alpos et al., 2021; Xie et al., 2021), which was likely to improve the quality of life of a person with diabetes. In this context, post‐thermal treatment (Yang et al., 2019), including cooking (Rehman & Shah, 2005) and baking (Naseer et al., 2021), was proposed to discover the influence of post‐thermal treatment on the crystal structure and eGI of GPS‐GMS‐D, which could potentially provide proper suggestions for post‐thermal treatments.…”

Sensory quality of upcycled legume water: Expectation vs. reality

“…Moreover, the panelist noticed that the control appeared to be more like a liquid than the other samples. The addition of legumes to bread could increase hardness, cohesiveness, springiness, chewiness, and resilience when Ca concentration was increased (Alpos et al, 2021). In a study on lentil-based tofu, calcium sulfate (CaSO 4 ) and chitosan affected the gel properties, such as hardness and cohesiveness, modifying the textural profile of tofu products (Jao et al, 2022).…”

Understanding In Vivo Mastication Behaviour and In Vitro Starch and Protein Digestibility of Pulsed Electric Field-Treated Black Beans after Cooking

“…All PEF-treated beans were then cooked at 80 • C for 60 min and their texture properties were determined. The texture profile analysis (TPA) for each cooked black bean sample type (approximately 20 g to allow at least 8-10 independent texture analyses per sample) was conducted using a texture analyser (TA-HD plus, Stable Micro Systems, Surrey, UK) based on a double compression or 'two-bite' test, as described by Alpos et al [16]. The samples were compressed at 50% strain (5 beans per compression) using a 50 mm diameter cylinder probe attached in a 250 kg load cell at a test speed of 1 mm/s.…”

“…Total starch of the oral bolus was determined according to previous work [16] using the total starch assay kit (Megazyme, Bray, Wicklow, Ireland). Protein digesta (0.5 mL) were collected at 0, 30, 60, and 120 min of the gastric phase (after addition of simulated gastric solution) and at 0, 20, 30, 40, 60, 90, 120, 180 and 240 min of the small intestinal phase (after addition of simulated small intestinal solution).…”