اثر فرايند استيلاسيون و اتصال‌عرضي بر خصوصيات فيزيكوشيميايي ، عملكردي و ساختاري نشاسته نخود (واريته جم)

(The Effect of Acetylation and Cross-linking on the Physicochemical, Functional and Structural Properties of Iranian Pea Starch (Jam variety

نشاستۀ نخود يك محصول جانبي در فرايند استخراج پروتئين است. نشاستۀ نخود در كاربردهاي صنعتي استفاده مي‌شود، اما به‌دليل خصوصيات عملكردي ضعيف در صنعت غذا استفادۀ چنداني ندارد. خواص نشاسته را مي‌توان با استفاده از برخي روش‌ها تعديل نموده و بهبود بخشيد. هدف اين تحقيق بررسي تأثير دو روش ايجاد اتصال عرضي در دو سطح 0/05 درصد و 0/07 درصد و استيله‌كردن در دو سطح 6 درصد و 8 درصد بر خصوصيات فيزيكوشيميايي، ساختاري و عملكردي نشاستۀ نخود واريتۀ جم بود. ميزان آميلوز نشاستۀ معمولي 0/41±48/59 درصد بود كه بعد از فرايند استيلاسيون افزايش يافته؛ اما اتصال عرضي ميزان آميلوز را كاهش داد. ميزان استيلاسيون و درجۀ جانشيني با افزايش درصد استيلاسيون افزايش يافت. با افزايش اتصال عرضي قدرت تورم كاهش معني‌داري نشان داد اما با افزايش درصد استيلاسيون، اين پارامتر افزايش معني‌دار نداشت (سطح0/05

Pea starch is a by-product of protein extraction of pea processing. Pea starch is used in industrial applications, but due to the poor functional properties are not used in the food industry. Strach properties can be improved or modified with different methods. The aim of this study was to evaluate the effectt of to modification mehods at two levels 0.05% and 0.07% and acetylation at two levels 6% and 8% on physicochemical, structural and rheological properties of pea starch (Jam variety). The amylose content of native starch was 48.59 plusmn;0.41 that increased with acytylation reaction but cross-linking reduced this value. Acetylation and substitution degree increased with increasing acetylation degree. Swelling power of cross-linked starch decreased significantly with increasing cross-linking level; but this parameter for acetylated samples were not significantly increased (P gt;0.05). Syneresis of acetylated starch pastes redced compared to native one; but cross-linking process increased this value compared with native starch. 8% acetylated pea starch with 36.0 plusmn;1.5 percent significantly had minimum syneresis than other starch samples during storage. In addition, modification of structure of chemically modified pea starch was confirmed by FT-IR. Thermal properties of starches showed that the gelatinization enthalpy of acetylated and cross-linked starch decreased and increased, respectively. Due to the changes of various characteristics of pea starch after chemical modification, the starch samples are expected to have a different functionality compared with native starch.