Effects of young bamboo flour on techno-functional properties of extrudates produced from acidified rice flour

Young bamboo culm flour (YBCF) emerges as an innovative and sustainable ingredient for the food industry. In this study, the effects of YBCF substitution (0, 2.5, 5, and 7.5%), along with the addition of 0.5% (w/w) lactic acid and 0.5% (w/w) sodium chloride, were evaluated in rice flour (RF) extrudates. The inclusion of YBCF reduced specific mechanical energy by 9 to 22%, while expansion decreased by up to 8% in formulations containing higher YBCF levels and bulk density decreasing by up to 30%. The color of the extrudates was affected, showing decreased lightness (from 89.50 ± 1.00 to 86.58 ± 1.33) and increased red and yellow tones, attributed to non-enzymatic browning reactions. Regarding functional properties, there was a 20% increase in water absorption index (WAI) and a 61% decrease in water solubility index (WSI). Viscosity dropped by up to 37% (from 366.25 ± 16.62 to 231.25 ± 10.96 cP), while chemical composition revealed high glucan content (up to 56%) and no detectable xylan. No significant differences in bifidogenic activity were observed among the whole extrudate formulations, although physically separated YBCF particles exhibited differences, with the 5% YBCF treatment showing higher activity than the 2.5% and 7.5% treatments. The results indicate that YBCF and lactic acid alter the technological properties of extrudates, improving hydration but reducing expansion. Therefore, YBCF stands out as a sustainable alternative for functional foods like fiber-enriched extruded snacks, meeting the growing demand for healthier and more environmentally responsible products.