Seyed Amir Tavakoli Lahijani; Fakhri Shahidi; Mahmoud Habibian; Arash Koocheki
Abstract
[1]Introduction: Bread has a major role in the diet of people in Iran. One of the important factors affecting the quality of bread is the quality of wheat flour protein called gluten. Gluten is the principal structure forming elements of most baked products, contributing to the elasticity, cohesiveness ...
Read More
[1]Introduction: Bread has a major role in the diet of people in Iran. One of the important factors affecting the quality of bread is the quality of wheat flour protein called gluten. Gluten is the principal structure forming elements of most baked products, contributing to the elasticity, cohesiveness and viscosity characteristics of the dough. Thus, gluten substantially control the quality of wheat flour based products. Due to the importance of the role of gluten and the requirement for improving the flour quality, providing a simple, economical, and efficient method to improve the technical quality of wheat and bread is also an important and controversial challenge. Oxidizing agents are generally added to the wheat flour to accelerate the natural maturing and the flour becomes paler and yields dough with improved baking properties. However, increasing concern about their adverse effects has highlighted the need for the development of alternative oxidants. Atmospheric cold plasma (ACP) is an emerging advanced oxidation process which has recently drawn considerable interest from food scientists. Therefore, the objective of this study was to investigate the effect of non-thermal plasma treatments on the properties of wheat flour.
Materials and Methods: For this purpose, medium wheat flour was prepared from local silages and treated with ACP at 25V for 0, 2, 4, 6, 8 and 10 min. Chemical composition of flour samples (moisture content, protein and ash) were determined using standard methods (AACC, 2002). Color properties, damaged starch water soluble index, wet gluten, gluten index, zeleny and falling number values, water and oil absorption capacities, swelling power and solubility of wheat flour samples were also measured.
Results and Discussion: The results obtained from the measurement of properties for the treated and untreated flour showed that the water and oil absorptions, swelling power, and solubility, wet gluten, gluten index, Zeleny number and whiteness increased significantly with increasing time, while the pH, moisture content, b * and a * indices, were decreased by plasma treatment. In addition, the results showed that ACP conditions have a significant effect on functional properties that can be created floursand products with various characteristics. The results showed that plasma treatment affected the gluten index and wet gluten and techno functional properties of wheat flour. Overall, this study demonstrated that non-thermal plasma is a quick, efficient way to improve the technological properties of wheat flour, as an alternative to chemical oxidants
Maryam Tamsen; Nafiseh Soltanizadeh; Hajar Shekarchizadeh
Abstract
Introduction: The main part of the further-processed foods especially fish, seafood, poultry, cheese and vegetables market is constituted of battered and breaded products. The annual consumption of battered and breaded products in some countries such as Europe, Japan, and Oceania is approximately 2 billion ...
Read More
Introduction: The main part of the further-processed foods especially fish, seafood, poultry, cheese and vegetables market is constituted of battered and breaded products. The annual consumption of battered and breaded products in some countries such as Europe, Japan, and Oceania is approximately 2 billion pounds. Frying of battered and breaded products is used to improve their quality factors which are mainly crispness, texture, moisture and oil contents, porosity, color and appearance, flavor and nutrition. Crispy outer layer and the moist and juicy interior as pleasant textural characteristics are created in fried foods. Chicken nugget which is made from chicken meat is breaded or battered, then deep-fried or baked and finally is quick frozen. Chicken nugget is composed of four layers including paste, pre-dust, batter and breaded layers. Amaranth is one of the pseudo-cereal grains which belongs to the Amaranthaceae family. The color of amaranth seed varies from milky white to yellow, golden, red, brown, and black. This plant has high nutritional and biological value. Amaranth seed contains starch (61/4%), protein (16/5%), unsaturated fats (5/7%), fiber (20/6%), vitamins (E, B2 and C), minerals (calcium, magnesium, zinc and iron) and phenolic compounds. The purpose of this study was to replace wheat flour with amaranth flour in order to reduce wheat grain dependence, improve the nutritional value of nuggets as well as explore the production possibility of a new product for celiac disease.
Materials and methods: In order to investigate the effect of replacing of wheat flour by amaranth flour in nugget formulation, amaranth flour was used at 0, 50 and 100% levels separately in chicken paste, batter dough, and all layers of nugget (chicken paste, predust, and batter dough). Then, the chemical composition and pH of chicken nugget, chicken paste emulsion stability, cutting force, oil absorption, porosity, cooking loss, degree of oxidation, color and sensory characteristics of produced nuggets were evaluated.
Results and discussion: Results showed that increasing the substitution percent would increase the nutritional value of nuggets. The pH of all produced nuggets containing amaranth flour was higher than the control sample and pH reduction occurred slower in them during 13 days of storage at 4 ° C. Emulsion stability was also affected by the replacement rate and reached the maximum content at full replacement. Samples with 100% incorporation of amaranth flour had the highest emulsion stability due to the presence of polar lipids and globulin in amaranth flour which are surface active agents. However, 50% substitution of wheat flour with amaranth flour in chicken paste significantly decreased emulsion stability as this sample had the lowest emulsion stability. It seems that the interaction of amaranth albumin proteins with wheat gluten proteins reduced soluble proteins, which caused emulsion stability reduction of chicken paste containing both amaranth flour and wheat flour. Also the presence of amaranth flour in nuggets significantly increased oil absorption, porosity, cutting force and cooking loss. Oil absorption of nuggets increased by increasing the amount of amaranth used in nugget production, as the control nuggets had the lowest oil absorption. Albumin proteins which are present in amaranth flour have high oil absorption capacity. Amaranth flour has low viscosity in gelatinization owing to the low amylose content of amaranth starch, which decreases the absorption of batter dough to the chicken paste and as a result cooking loss will increase. Porosity of nuggets increased by increasing the amount of amaranth flour in prepared nuggets. Globulin which constitutes about 20% of amaranth proteins is a good foaming agent. Entrapment of air bubbles by globulin caused porosity increase in nuggets. In addition, the results of moisture content of nuggets showed moisture removal of nuggets containing amaranth flour after frying. Steam pressure of evaporated water caused porous tissue in samples. Hardness, chewiness, gumminess, springiness, and cohesiveness of nuggets containing amaranth flour increased. The cutting force was increased significantly as a result of the amount of amaranth flour of nuggets as was expected. About the oxidation, increasing the substitution rate reduced the amount of malonaldehyde in the early days and reduced the oxidation process in 13 days of storage at 4 ° C. High amounts of phenolic compounds were found in amaranth flour, which could reduce lipid oxidation and spoilage of nugget. Amaranth flour darkened nuggets and by increasing amaranth content, that amount of L (brightness), a (redness) and b (yellowness) declined. Lightness of the outer layer of nuggets decreased by increasing the amaranth amount of nugget, due to the presence of bran and betacyanin pigment in amaranth flour which make it darker than white flour. Wheat flour could be substituted with amaranth flour in nugget production, increasing the nutritional value of product by increasing protein, fiber and minerals levels, with no undesirable effect on total acceptance of consumers.
Forough Zarenejad; Seyed Hadi Peighambardoust; Sodeif Azadmard Damirchi
Abstract
Wheat germ is a by-product of milling industry rich in fiber, tocopherol, unsaturated fatty acids, polyphenol, minerals and protein. In this study, effect of adding raw and stabilized wheat germ on the characteristics of cake batter such as specific gravity, viscosity and cake properties such as volume, ...
Read More
Wheat germ is a by-product of milling industry rich in fiber, tocopherol, unsaturated fatty acids, polyphenol, minerals and protein. In this study, effect of adding raw and stabilized wheat germ on the characteristics of cake batter such as specific gravity, viscosity and cake properties such as volume, apparent density, solid density, porosity, water activity, moisture and firmness was studied. Raw wheat germ was stabilized by steaming for 15 min and subsequent drying at 80 °C for 20 min. It was then ground and added to cake formulation at levels of 5, 10, 15 and 20 % (on flour wet basis). Results showed that adding wheat germ changed the characteristics of cake batter. With increasing amount of raw and stabilized wheat germ, specific gravity and viscosity of cake batter increased and reduced, respectively. Important difference was observed in the physical characteristics between wheat germ enriched and control cakes. Increasing wheat germ in cake formulation decreased cake volume and porosity, while apparent and solid densities were increased. Investigation of moisture content and firmness, in several days of storage, showed that the cakes enriched with raw germ had the higher moisture content than those enriched with stabilized germ. Cakes enriched with stabilized wheat germ had the highest firmness. Incorporation of stabilized wheat germ by controlling its detrimental effects relating to lipase activity which leads to fat rancidity, could favor production of a functional cake with improved nutritional properties.
