مجله پژوهشهای علوم و صنایع غذایی ایران (May 2022)
Production of low-fat doughnut using triticale flour and Basil gum and investigation of the effect of green cardamom essential oil on its shelf life
Abstract
Introduction: Doughnuts are fried foods that absorb significant amounts of oil, and commercial doughnuts made from wheat flour typically contain 24 to 26 percent oil. Fresh doughnut is soft and has a pleasant taste and aroma. One of the main ways to enrich bakery products is to mix wheat flour with other flours. Triticale has a higher percentage of protein compared to wheat, rice, corn, rye and oats and is in good condition in terms of essential amino acids. Lysine in triticale is higher than wheat and less than rye. Also triticale has the same amount of vitamins as wheat. The positive properties of gums extracted from native seeds such as basil can be used to reduce oil absorption and improve shelf- life of fried bakery products. Basil seeds are soaked in water due to the presence of polysaccharides, the outer pericarp swells and turns into a gelatinous substance. Green cardamom with scientific name of Elettaria cardamomum belongs to Zingiberaceae family. Cardamom is one of the most widely used aromatic condiments in some foods, breads, sweets, especially jams. 23 compounds have been identified in green cardamom essential oil, the highest composition (31.53%) belonging to Eucalyptol. Therefore, in this study, enrichment the wheat flour of fried fermented doughnuts by replacing part of wheat flour with triticale flour, reducing oil absorption by using basil seed gum and improving antioxidant and sensory properties and reducing fungal activity in the presence of green cardamom essential oil were investigated. Material and Methods: In the first part of this research, Triticale flour at 0, 15 and 30% and Basil seed gum at 0, 0.50 and 1% were used to improve the quality and decrease oil absorption of fermented doughnut. Control doughnut formulation had 500 g wheat flour, 20 g milk powder, 4 g salt, 80 g oil, 12 g baker’s yeast, 80 g sugar, 500 ml water, 100 g egg and 1 g vanilla, 1.5 % guar gum and 0.5 % xanthan gum. Moisture, specific volume, porosity, firmness, crust color and oil absorption were evaluated. To study the effect of processing parameters on crust color components of doughnut, the RGB color space images were converted to L*a*b space. For determination of doughnut porosity using image analysis, the color images were first gray scaled and then thresholded using isodata algorithm. The porosity was measured from the ratio of white to the total numbers of pixels. Results were reported as the average of three replications. In the second part of this research, Cardamomum essential oil at 0, 50, 100, 150 and 200 ppm were used to improve antioxidant and sensory properties and decrease microbial contamination of doughnut. . In order to assess significant differences among samples, a complete randomized design of triplicate analyses of samples was performed using the Mini-Tab17. Tukey’s new multiple range tests were used to study the statistical differences of the means with 95% confidence. Result and Discussion: The results of the first part showed that the sample contained 15% triticale flour and 0.50% gum with the highest specific volume (3.4 cm3g-1) and porosity (0.81) and the lowest firmness after one week of storage (11.91 N) and was introduced as the best example of the first part. Also, the results of oil absorption showed a decrease of 29.83% in the selected sample (0.17 g/g dry matter) compared to the control sample (0.24 g/g dry matter). The moisture content of the mentioned sample was 21.09% one week after production and L*, a* and b* of crust color was 55.27, 8.86 and 11.91, respectively. Brightness and redness of this sample was more than the control. The results of second part showed that cardamom essential oil had antioxidant activity in all concentrations. Also, the results indicated the concentrations of more than 50 ppm of cardamom essential oil can be considered as an antifungal agent and inhibit positive growth in doughnut. The microbial load of samples containing 100, 150 and 200 ppm had 3.97, 3.81 and 2.94 log cfu g-1 after 15 days of production, respectively. The microbial load of these samples was 51.05, 53.03 and 63.75% less than the sample without essential oil (10.11 log cfu g-1). Finally, the results of sensory evaluation showed that the sample containing 15% triticale flour, 0.50% basil seed gum and 100 ppm cardamom essential oil had the highest overall acceptance score and this sample is introduced as the best sample of this study.
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