Unleashing the potential of flash vacuum expansion: an innovative approach for andean blackberry (Rubus glau- cus Benth) processing

Andean Blackberry fruits (Rubus glaucus Benth) have promising market potential with notable nutritional and antioxidant properties; however, their limited 3-6day shelf-life presents considerable challenges. A flash vacuum expansion (FVE) process coupled with vacuum de-pulping was used to obtain puree from blackberry fruits. Different steam heating holding times (53, 75, 85, and 95 s) were tested at a pressure of 130 kPa. After FVE and vacuum de-pulping (5kPa), various parameters, including alcohol insoluble residues (AIR), residual activity of polyphenol oxidase (RAPPO), anthocyanins, ascorbic acid and ellagitannin retention, rheological properties, and microbial reduction, were evaluated in the purees. Optimal steam heating time of 85 seconds was selected for the FVE process, showing outstanding retention rates of 98% for cyanidin-3-O-glucoside and 88% for ascorbic acid, along with enhanced ellagitannins extraction from torus and seed blackberries into the puree. The purees displayed a gradual shear-thinning flow behavior, positively correlated with the increase in %AIR. A reduction greater than 5 Log10 CFU / mL was achieved for molds, yeasts, aerobic mesophilic, and coliforms counts for all the treatments. Nectar and sweetened puree products developed from the optimal FVE processed puree, received favorable acceptance from consumers, with a high intention to purchase. The findings demonstrated that this innovative process has great potential for developing of high-quality products.