Physicochemical properties and emulsification properties of maize starch modified by hydrochloric, phosphoric and tartaric acid

Native maize starch (NS) dispersions treated with hydrochloric (HA; 1M, 2M), phosphoric (PA; 1M, 2M) and tartaric acid (TA; 0.67M, 1.33M) were investigated in terms of their morphological, structural and physicochemical properties, including emulsification capacity. The molecular weight of starch was affected by both factors (acid type and concentration). The mean molecular weight (Mw) was decreased by 89% and 11% after treatment with HA (1M) and PA (1M), respectively. TA-treated starch resulted into three distinct size distributions, one of which showed larger Mw as compared to the NS. Dynamic light scattering measurements revealed that the modified starches in aqueous environment were spread in at least two distributions, one of them showing particle sizes higher than 200 nm, whereas the other lower than 200 nm. Clarity of treated starch pastes decreased in the following order: HA > TA > PA > NS. Generally, O/W emulsification and stability properties deteriorated with starch modification. tau Alpha yielded the most stable emulsion among the modified starches.