مروري بر كاربرد و اثرات استفاده از نشاسته هاي اصلاح شده در توليد و كيفيت نان

An overview on the application of modified starches for breadmaking

بيش از يك قرن است كه نشاسته هاي اصلاح شده توسعه يافته و در صنايع مختلف مانند صنايع غذايي، نساجي و كاغذسازي مورد استفاده قرار مي گيرند. اخيراً، نشاسته هاي اصلاح شده ي شيميايي مانند نشاسته هاي استريفيه، اتري و يا كراس لينك شده (با اتصالات عرضي) در مواد غذايي مختلف مانند اسنك ها، نان ها و كيك ها براي بهبود كيفيتشان به كار گرفته مي شوند. در فرآيند توليد نان، نشاسته نقش مهمي را در بافت و كيفيت خمير و نان ايفا مي كند. بنابراين، نشاسته هاي اصلاح شده توسعه يافتند تا بر خصوصيات نامطلوب نشاسته دست نخورده غلبه كنند. مقاله حاضر نيز به روش هاي مختلف اصلاح نشاسته و اثرات استفاده از اين نشاسته ها در توليد نان مي پردازد.

Modified starches have been investigated and developed for more than a century and have various applications in food, paper and textile industries. Recently, chemically modified starches such as esterified, etherified and/or cross-linked starches have been widely used for various prepared foods such as snack foods, breads and cakes to improve their quality. In breadmaking, starch is a major component and plays an important role in texture and quality of dough and bread. Th erefore, modified starches, which were developed to decrease undesirable properties of native starches, also affect the properties of dough and quality of bread. Th e modified starches could be used to substitute up to 20% for wheat flour without deterioration of bread quality. Generally, the substituted flours gelatinized more quickly and had higher peak viscosity than the wheat flour alone. Th e dough made from the substituted flours exhibit weaker and less stability than that made from the wheat flour. Th e breads substituted with hydroxypropylated starch were less firm and retained softness during storage longer than those with other modified starches or wheat flour alone. Th e acetylated starch also improved the firmness of bread crumb during storage, whereas cross-linked starches made the bread crumb harder because the chemical cross-linking retained the granular structure of starch in the gluten network resulting in increase in the firmness of bread crumb. Th us, the different kinds of chemically modified starches played the different roles in the texture and quality of doughs and breads.