Utilization of Fiber Obtained from Barley Malt Pulp as a Fat Substitute in the Production of Low Fat Mayonnaise

Mayonnaise is one types of sauces that has always been loved and preferred by consumers because of its unique texture and taste. Sauce is a semi-solid or liquid food ingredients that consists of emulsifying edible vegetable oils (at least 66%) in a liquid phase including vinegar, water, lemon juice, and egg yolk (Bortnowska and Makiewiewicz, 2006). According to the National Standard of Iran (No. 2454), if the amount of fat in mayonnaise is reduced by at least 25% (from 66% of fat), it is considered reduced fat mayonnaise, and if it is reduced by 50% in fat, mayonnaise is considered low-fat. (National Standard of Iran 2454, 1394). Fibers are edible parts of plants or similar carbohydrates that cannot be absorbed in the gut and only irritate the gut. Dietary fiber contains polysaccharides, oligosaccharides, lignin and related plant materials. Dietary fiber intake can reduce the risk of cardiovascular disease, high blood pressure, diabetes, obesity, cancer and some gastrointestinal disorders. They can alter tissue properties, eliminate hydration, stabilize high-fat foods and emulsions, and improve shelf life (Zhang et al., 2017). Barley (Avena sativa L.) is an important crop with about 21 million tons annually production worldwide. The seed has been used to raise public awareness about the health benefits of beta-glucan, which helps lower blood cholesterol and glucose levels. Protein is the second most abundant element (12 to 20%) in barley after starch, which contains organic amino acids, due to its high lysine content because globulins make up 70 to 80% of total barley protein. Alcohol-soluble prolamins, on the other hand, are the main storage proteins in other cereals (Nito et al., 2015).

 In this study, nitrate, ethanol, methanol, chloroform, ethylene glycol and acetic acid were prepared from Merck Company (Germany) and sunflower oil from Rana Company, vinegar from Somayeh Company, salt from Aali Company, sugar from Pardis Company, mustard from Bijan Company and Barley Malt Pulp was prepared from Behnoosh Company. Chemical extraction method was used to extract fiber. (Salehifar and Fadai Noghani, 2013). To prepare the mayonnaise samples, the powder ingredients including salt, mustard and sugar, vinegar and water were first mixed well and uniformly with a mixer (IKA WERK, Germany). Then, according to the formulation, the fiber extracted from barley malt pulp was gradually added to the above mixture, which was stirring, and the eggs were added to the mixture and mixed thoroughly to obtain a uniform composition. At this stage, the oil was added dropwise with continuous pouring. Finally, the samples of mayonnaise prepared were kept at refrigerator for further analysis. In all samples, the amount of sugar (11.5 g), white vinegar (23.1 g), eggs (39.45 g), salt (4.50 g), water (24.6 g) was constant (Bostani et al., 2011). In this study, in order to reduce the amount of oil, it was replaced with fiber extracted from barley malt pulp at five levels of 0, 5, 10, 15 and 20% (w / w).

 The effect of replacing different percentages of fibers extracted from barley malt pulp with fat at levels (5, 10, 15 and 20%) on physicochemical properties (fat, fiber, ash, viscosity and colorimetry (L*) a*, b*) and sensory characteristics (taste, smell, color, texture and general acceptance) were determined using analysis of variance at 5% probability level. Various properties of low-fat mayonnaise showed that as the percentage of barley malt fiber increased, the amount of fat, radiance and yellowness in low-fat mayonnaise treatments (P <0.05) decreased, and the addition of fiber increases the viscosity, fiber, ash and redness of mayonnaise, treatments (P> 0.05) as well as protein content. In the treatments, which was statistically significant (P> 0.05), the results of sensory evaluation of mayonnaise samples showed that the addition of fiber extracted from barley malt pulp resulted in a significant reduction in taste, texture, color and the general acceptance of mayonnaise samples (P <0.05), while the decrease in odor score was not statistically significant (P> 0.05), so that the treatment containing 20% barley malt fiber had the lowest sensory score (taste). Smell, texture, color, acceptance k Li) and treatments containing 5 and 10% barley malt fiber received the highest sensory scores (taste, odor, texture, color, general acceptance) from the panelists.

 According to the results, treatment 3 (containing 10% barley malt fiber) was introduced as the best treatment in the present study.