Development of Gluten-Free Biscuits From Rice Flour-Pineapple Stem Starch Blends: Physicochemical Properties, In Vitro Starch Digestibility, Estimated Glycemic Index, Sensory Evaluation, and Storage Stability.

Pineapple stem starch (PSS) is a valuable source of nutritional resistant starch (RS), offering great potential as an alternative ingredient for producing functional gluten-free biscuits. This study aimed to develop healthy gluten-free biscuits using blends of all-purpose rice flour (RF) and PSS and to evaluate their physicochemical properties, in vitro starch digestibility, estimated glycemic index (eGI), sensory attributes, and storage stability. The biscuits were prepared by combining RF and PSS at various ratios of 25:75, 50:50, 75:25, and 0:100, in comparison to gluten-free control biscuits made with 100% RF. As the PSS content increased, the biscuit thickness increased, whereas hardness decreased. In terms of starch digestibility, the RS content of biscuits increased but eGI decreased with increasing PSS incorporation. Sensory evaluation revealed that biscuits containing 75% PSS received the highest liking scores across all assessed parameters. This optimum formulation (25:75 RF-to-PSS ratio) had an eGI of 60.04, which falls within the medium-GI category. In addition, both the control biscuits and the 75% PSS biscuits maintained peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) within the acceptable limits throughout the storage period. The findings demonstrate that PSS is a promising functional ingredient for gluten-free biscuits. Incorporating 75% PSS and 25% RF into the biscuit formula effectively produced reduced-GI gluten-free biscuits, demonstrating their potential as a functional food.