Valorization of resistant starch from acorns as a new ingredient for chocolate milk puddings

Aim: Despite being a fruit rich in resistant starch, acorns remain undervalued. Resistant starch is known to improve food acceptability when compared to traditional insoluble fibers, and recent research suggests the usage of acorn starch as an additive in fermented yogurt and milk products. Furthermore, non-thermal technologies such as high hydrostatic pressure and pulsed electric field can produce clean-labelled starches. Milk puddings are widely consumed all over the world and are usually produced using representative amounts of starch, making them an enticing food matrix for incorporating acorn starches. Hence, the effects of replacing commercial corn starch with acorn starch extracted by high hydrostatic pressure and pulsed electric field on the nutritional composition, functional and sensorial properties, and shelf-life of puddings were studied. Methods: Extraction of starch from Quercus robur acorns was performed using high hydrostatic pressure or pulsed electric field. Extracted starch was used in chocolate puddings, replacing commercial corn starch. Shelf-life storage and microbiological analysis were conducted over 28 days, along with texture, color, pH, and nutritional composition assessments. Rheological properties, scanning electron microscopy, in vitro digestion, and soluble sugar, fatty acid, and salt content analyses were performed. Sensorial analysis was conducted with 71 volunteer panelists to evaluate the acceptability, preference, and similarity of puddings. Results: Replacing the commercial corn starch with acorn starch improves the rheological properties of puddings and has no negative impact on the nutritional composition, internal structure, or in vitro digestibility. Sensory analysis revealed that panelists preferred the acorn starch puddings over the control. After 28 days of storage at 4°C, there was a greater stabilization of the color parameters and an improvement in textural parameters of puddings without compromising microbial safety. Conclusions: This study demonstrates the potential usage of starch from acorns in food applications, a fruit that is so undervalued.