Title : Octenyl succinic anhydride modification of native cacahuacintle maize starch: Effects on functional and digestive properties
Abstract:
Maize is a valuable source of starch; however, many native genotypes remain underexplored. The genetic diversity and postharvest conditions of maize contribute to variations in starch structure, nutritional value, and techno-functional properties. Mexico, recognized as the center of origin, domestication, and diversity for 68 registered native maize landraces. Native starches often present limitations such as high retrogradation tendency, elevated viscosity, low thermal stability, poor freeze-thaw resistance, limited processing tolerance, and opaque gels. Esterification with octenyl succinic anhydride (OSA) enhances starch emulsifying capacity and amphiphilic behavior by substituting hydroxyl groups with hydrophobic moieties. In this study, two cacahuacintle maize varieties (MA1 and MA2), endemic to the State of Mexico but from distinct locations, were used to extract native starches (MS1 and MS2), which were compared to a commercial normal maize starch (CS). Scanning electron microscopy (SEM) revealed polyhedral granules in CS, while MS1 and MS2 granules were predominantly semi-spherical. Fourier-transform infrared (FTIR) spectroscopy confirmed characteristic polysaccharide peaks in all samples, with notable differences in their hydrated and ordered structures. X-ray diffraction indicated a typical A-type crystalline pattern across samples, with crystallinity values ranging from 21.07% to 25.37%. MS1 and MS2 exhibited higher solubility, swelling power, and water retention capacity than CS, although CS demonstrated superior oil-holding capacity. Resistant starch content was greater in MS1 and MS2. OSA modification, validated through FTIR and morphological analysis, reduced starch digestibility while increasing slowly digestible and resistant starch fractions. Enhanced interactions among OSA-modified starch chains contributed to improved resistance to enzymatic hydrolysis. Additionally, pasting, and rheological properties were diminished post-modification. These findings suggest that OSA-modified starches derived from native Mexican maize have promising applications in the development of stable, low-calorie, high-moisture food products.
