Document Type : Research Article
Authors
Department of Food Science and Technology, Faculty of Agriculture, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan, Iran.
Abstract
Introduction: Legumes are suitable sources in nutraceutical properties due to existence of anticancer, antioxidant and also significant antimicrobial substances. Different processing such as soaking, peeling and germinating improves nutritional value and bioavailability of minerals such as calcium, iron and phosphorus content of legumes and based on the literature review, germination is the best method among the others. The results of previous researches demonstrated significant improvement of nutraceutical and farmoceutical properties of products due to germination. In legumes, sprouted lentil has higher nutritional value such as minerals and essential amino acids than others. Cereal based products, especially products of wheat flour such as bread, pastries, biscuits and etc are used generally as a staple food around the world. Cake is one of the widely used confectionary cereal based product that its nutritional quality is important in public health. According to deficiency of wheat flour from many essential amino acids and important minerals such as iron, the aim of present study was to employ natural enrichment of cake with sprouted lentile and improving the qualitative characteristics of products using active gluten and hemicellulase enzyme. Due to the existence of problems in enrichment of wheat flour with iron due to difficulties in uniform distribution of particles and creation of unsuitable organoleptic properties in the products, currently, iron enrichment is limited to whole flour in Iran. Therefore, the results of the present research could an alternative way for flour enrichment with iron and other nutrients.
Materials and method: In order to prepare sprouted lentil flour, the “official” lentil variety was prepared and treated at ambient temperature (24°C) and suitable humidity (90%) in dark place in order to germinate and increase the shoot height to 1.5 cm. The sprouted lentils were dried at room temperature in shadow. Then, they were milled and sieved in order to achieve suitable particle size. At the beginning step, sprouted lentil flour and wheat flour were evaluated in terms of protein, moisture, ash, fat and minerals such as iron, calcium, potassium and phosphorus. After numerous pre-tests by experts in cereal technology, the usable quantities of sprouted lentil flour according to organoleptic characteristics of the product, was considered 25% of batter’s flour. Improving the textural characteristics of products due the negative effects of germinated lentils flour was considered using independent variables of present study (hemi-cellulase enzymes at 0, 25 and 50 ppm levels and active gluten powder at %0, %1/5 and %3). Sprouted lentil flour was treated for 30 minutes with enzyme before using in batter formulation. Prepared samples with 25% replaced sprouted lentil with wheat flour and hemicellulase (0, 25, 50 ppm) and active gluten (%0, %1.5, %3) were investigated in terms of volume, bulk density, color properties of crust and crumb, moisture content, textural properties (hardness, cohesiveness and springiness) and also sensorial properties. Prepared product based on optimized formulation according to the results of chemical, physical and sensorial analysis was evaluated in staling rate, the quantities of fat, protein, ash, fiber and minerals such as iron, calcium, phosphorus, potassium and its results were compared to control. Data was analyzed according to the factorial experiments based on completely randomized design by SAS software (version 9.2), and the means were compared by LSD test at 5 significance percent level. Statistical evaluation of sensorial properties was also done based on qualitative method of Kruskal-Wallis.
Results and Discussion: In chemical composition of wheat and sprouted lentil flour, there were significant differences between two samples in terms of protein, ash, and minerals content such as iron, calcium, phosphorus and potassium. But, there was no significant difference in fat content. The quantity of iron in lentil flour was five times more than that of wheat flour, calcium was double, potassium was seven times and phosphorus was six times more than that of wheat flour. Also, sprouted lentil flour showed higher protein content than wheat flour. Addition of sprouted lentils to batter formulation increased moisture content of the sample than the same one prepared only with wheat flour. Gluten and hemicellulase had significant effects on reducing the apparent density of samples and improving the physical, sensorial and textural characteristics of the product. In this regard, the hardness of sample’s crumb were decreased and theirs cohesiveness and springiness were increased significantly. According to the results of the present study, the addition of gluten and hemicellulase enzyme was improved color properties, especially in crust position. Therefore, independent variables were effective in improvement of qualitative properties of products. Finally, the optimal sample based on physical, textural and sensorial evaluation was introduced a sample with 25% sprouted lentil flour, 3% active gluten and 50 ppm hemicellulase enzymes. The optimum sample was closed to wheat control sample in the case of the qualitative characteristics. Comparison of textural characteristics of optimum and control samples during storage was indicated the similar characteristics of them. Sprouted lentil flour was a rich material in fiber with high water binding capacity in technological point. Therefore, it improved moisture retention and softness of texture. As well as, comparison the textural qualitative characteristics of the selected and control samples (prepared with wheat flour completely without additives) was shown a very high affinity in them. The products made with sprouted lentil had significantly higher nutritional value in protein, ash, crude fiber and minerals such as iron, calcium, potassium and phosphorus content than control. The iron content of optimum sample was more than twice of the control. Therefore, the results of the present research are effective in production of the functional product with improved nutritional characteristics. Due to the unique nutritional value of grain, more sprouted bean is recommended to use in food product formulation, and at the same time suitable additives are used for reducing their impact on the textural and sensorial properties of product.
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