Green-assisted extraction of babassu (Attalea speciosa) mesocarp starch: impact of multi-enzymatic and physical strategies on multi-scale structure and techno-functional properties

Babassu coconut is predominantly found in Brazil and primarily exploited for the high-value kernel oil. This industry generates large amount of babassu mesocarp (23% of the fruit), an underutilized source of non-conventional starch. However, the complex polysaccharide matrix of the mesocarp remains a challenge for efficient starch recovery. To date, no research has explored green-assisted starch isolation for this biomass. Consequently, this study evaluated how different green wet-milling strategies modulate the yield, purity, multi-scale structure, and techno-functional properties of isolated babassu mesocarp starch (BMS). The investigated methods included wet-milling in cold-water (CW), warm-water (WW), enzymatic (EZ) using a multi-enzyme complex (Viscozyme ® L), ultrasound-assisted (US), and sequential combinations (EZ/US and US/EZ). Contrary to expectations for non-traditional technologies, the enzymatic complex and the combined methods did not enhance starch yield or purity. Furthermore, US-assisted extraction significantly reduced starch yield and induced structural damage to the released granules, as reflected by a reduction in gelatinization enthalpy (12.55 J/g). While all strategies preserved the pale yellowish color, bimodal particle size distribution, higher apparent amylose content (31.70-40.21%), and C-type crystalline pattern, the isolation method was a key factor in starch purity and a tool for tailoring techno-functional properties and pasting behavior, having EZ and US treatments lower retrogradation tendency. Therefore, among the studied methods, CW milling is the most cost-effective and sustainable route for industrial-scale production of high-purity (≥ 95%) native starch. From a techno-economic perspective, these findings demonstrate that BMS can be isolated without the costs associated with enzymatic inputs or high-energy physical treatments.