Properties of starches conjugated with lysine and poly(lysine) by the Maillard reaction

Native potato starch (PS), carboxymethyl potato starch (CMS), and corn starch phosphate monoester (PCS) were conjugated with lysine (Lys) and poly(lysine) (PL) by the Maillard reaction. The increased yellowness of each reaction mixture showed the development of browning, suggesting the conjugation of starch and Lys or FL. The Lys and PL contents in the conjugates were 0.12-0.68% and 2.8-4.3%, respectively. Conjugation with PL reduced the swelling and solubility of each starch. The CMS and PCS conjugates gelatinized at higher temperatures than either CMS or PCS alone and were hard to retrograde. The digestibility of each conjugate with alpha-amylase was lower than that of the original starch. The functional changes to the starches were most marked in the cases of starches with partial distortion of the internal structure as indicated for CMS and PCS.