Physicochemical, morphological characteristics, and functional properties of Brosimum alicastrum Sw. seed starch modified by HMT

Aim: Brosimum alicastrum Sw. (Ramón) seed is an underutilized starch source. Ramón seed starch (RSS) has been partially characterized, showing functional properties superior to corn starch. The modification of native starches is useful for obtaining desirable characteristics. HMT is a physical method that may alter the structure of starch by modifying its interaction with water. The study evaluated the effect of HMT on the chemical composition, morphological characteristics, and functional properties of RSS. Methods: RSS, corn, and wheat starches were isolated using a wet milling method. The starches were modified with HMT (10%, 20%, and 30% moisture). Chemical composition of flours and native starches was determined using AOAC methods. Total starch was determined by the AACC method, and amylose content was analyzed using the assay with DMSO, Concanavalin A, and amylolytic hydrolysis. Morphological characteristics were observed using scanning electron microscopy. Functional properties [solubility index (SI), water absorption capacity (WAC), and swelling power (SP)] of starches were determined using gravimetric methods. Results: RSS had higher mineral content (0.9%), total carbohydrates (98.5%), dietary fiber (11.2%), and lower protein content (0.2%) and total starch (82.0%) than wheat and corn starches. RSS yield was 31.2% and showed small granules (6.3 ± 1.4–11.5 ± 1.3 µm), with oval-spherical shape, and typical amylose content (24.9 ± 0.4%). No significant changes were observed in amylose-amylopectin content and morphology of granules after modification. The functional properties of RSS were significantly improved in HMT10%, reducing the peak at 80°C and increasing the SI (18.7 ± 0.8%), WAC (18.1 ± 0.2 g water/g starch), and SP (22.2 ± 0.2 g water/g starch) at 90°C, compared to native RSS, and greater than modified wheat and corn starches. Conclusions: RSS modified by HMT at 10% moisture gradually enhances its functional properties as temperature increases, and above that of corn and wheat starches, resulting in an attractive non-conventional starch with potential industry applications.