Reformulation of Biscuit and Oatcake Products With Nutritional and Environmental Benefits Using a Novel Palm Shortening Substitute

Abstract

This paper assessed the feasibility of replacing palm shortening with a novel sustainable ingredient composed of rapeseed oil, linseed meal, and beta-glucan (PALM-ALT) in hard-texture bakery products (biscuit and oatcake). There is currently no palm shortening alternative that is functional, sustainable, nutritionally-balanced, and competitive. The PALM-ALT ingredient was characterized by oil droplet size distribution, rheology, confocal microscopy, and scanning-electron microscopy, whilst the biscuits and oatcakes were profiled by sensory, texturometry, colorimetry, water activity, and moisture analyses. The PALM-ALT ingredient exhibited a stable emulsion-gel structure (32 µm oil droplet size, 62 Pa.s viscosity, 40 Pa yield stress). Linseed proteins contributed to the formation and stabilization of oil droplets, whilst linseed mucilage, oat beta-glucan, and aggregates of linseed proteins and/or beta-glucan (observed in the continuous phase) further stabilized the emulsion. Three formulations were prepared with either palm shortening, rapeseed oil, or PALM-ALT. PALM-ALT biscuits and oatcakes respectively showed an 86% and 75% saturated fat reduction in comparison with their palm-based control product. PALM-ALT products displayed similar sensory and instrumental profiles to their palm-based controls, whereas rapeseed oil formulations exhibited significantly different color, odor, and texture profiles than the controls (p < 0.05). Rapeseed oil biscuits showed a lower overall sensory quality than their palm-based control, whilst PALM-ALT oatcakes displayed a higher acceptability than the control and rapeseed oil products (p < 0.05). This study showed that PALM-ALT was able to replace palm shortening in hard-texture bakery formulations with maintenance of their sensory profiles, whilst providing nutritional and sustainability benefits.