Food Technology
Akram Arianfar; Mahtab Moradnia; Zahra Sheikholeslami; Ali Mohamadi Sani
Abstract
Introduction: Donut is a type of sweet fried snack that was produced as fermented and deep fried. The deliciousness and high energy of the donut has made it very popular among sweet products made from wheat flour. The lack of wheat and its sensitivity to changes in weather conditions as well as bad economic ...
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Introduction: Donut is a type of sweet fried snack that was produced as fermented and deep fried. The deliciousness and high energy of the donut has made it very popular among sweet products made from wheat flour. The lack of wheat and its sensitivity to changes in weather conditions as well as bad economic conditions in recent years requires that research in the field of replacing wheat flour with other grains. Quinoa is a rich source of protein (the essential amino acids lysine, methionine, cysteine, and threonine), magnesium, fiber, vitamin B, potassium, and other minerals such as iron. Quinoa seeds have less starch than other grains (wheat, barley, corn, and rice). The value of dietary fiber in quinoa is much more in comparison to other grains, it had about 31% insoluble fiber. Also, as a source of phytoestrogens, it prevents cancer, cardiovascular diseases, and osteoporosis. The main problem with quinoa used for human food is the presence of saponin in the outer shell of the seed. Saponins are considered anti-nutritional agents due to their hemolytic activity on red blood cells, bitterness, foaming ability, and inhibition of enzymes. Therefore, the most important step for using quinoa in food products is to remove saponin. The other problem with using saponin is too bitter hence causing bloating and heartburn. Ths study aimed to choose the best saponinization method from quinoa and the possibility of using the saponinization quinoa instead of wheat in donut formulation and investigated the quality, texture, and sensory properties of the donuts.Materials of methods: The methods for saponin removal include (maceration, microwave, ultrasound, wet method, and a combination of wet and dry method) were compared. Donuts were produced with quinoa flour at two levels of 20 and 40%. The Fiber, ash, and protein values of wheat flour, saponinized quinoa flour, and donuts with different levels of saponinized quinoa flour were measured. The effect of replacement wheat flour whit saponinized quinoa flour on oil absorption, texture, SEM, and sensory properties of donuts evaluated.Results and Discussion: A comparison between different methods of saponinization indicated that the ultrasound method had the minimum efficiency in saponin removal and the highest amount of saponin removal was in the wet and dry combined method, followed by the maceration method. The difference between the combined method and massage was not significant and had the most influence in extracting saponin from quinoa flour. Of course, the massage method is important from the point of view of the economy due to the long time of the process and the production of a lot of waste water so this method had the loss of nutrients in the quinoa. The highest amount of protein, fiber, and ash was obtained in saponinized quinoa flour and a donut containing 40% quinoa flour. The amount of firmness, elasticity, SEM, and sensory properties in the sample with 20% quinoa flour had similar characteristics to the control sample, but increasing the amount of quinoa flour reduced these factors. The oil absorption percentage in donuts containing 40% quinoa flour was higher than in other samples. The results of using saponinized quinoa flour on the sensory characteristics (color crust and crumbs, taste, smell, texture and overall acceptance) of donuts showed that donut with 20% quinoa was similar to the control sample and was acceptable for panelists but increased the concentration up to 40% wasn’t pleasant. Conclusion: In this study, the saponinized quinoa flour used in donut formulation to increase the nutritional value and reduced the calories of donuts also overcame the challenges of wheat shortage. The saponinization methods were compared to choose the method with the highest saponin removal. Then donut with saponinized quinoa flour was prepared. The use of saponinized quinoa flour instead of wheat flour increased the nutritional value of donuts. Adding saponinized quinoa flour to the donuts formulation significantly declined the oil absorptions. Generally, the donuts containing saponinized quinoa flour had relatively similar sensory properties to the donuts with wheat flour (commercial donuts). Therefore, it seems that saponinized quinoa flour could be used successfully to improve the nutritional value of donuts and also consumers' acceptance.
Zahra Sheikholeslami; Mahdi Karimi; Bahareh Sahraiyan
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 ...
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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.
Food Engineering
Hassan Sabbaghi
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. The use of additives, especially hydrocolloid compounds, in reducing the oil uptake in doughnuts is a practical method because there is ...
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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. The use of additives, especially hydrocolloid compounds, in reducing the oil uptake in doughnuts is a practical method because there is no need to make changes in the industrial design of the equipment. Usually, the level of these compounds used to achieve the desired properties in food systems is less than 2% dry basis. When these compounds are added to the dough, they form a gel as soon as possible, which has a high water holding capacity in contact with hot oil, and this will be effective in maintaining and controlling the moisture content of the product and preventing oil penetration. Controlling moisture outflow from the product reduces the rate of moisture migration and compounds from the food into the frying oil, and subsequent peroxidation reactions in the oil consumed are reduced, thus increasing the useful life of the oil. Therefore, in this study, the effect of xanthan gum and carboxymethylcellulose on doughnut quality characteristics was studied. Materials and Methods: For this purpose, in the formulation of doughnut dough, xanthan gums, carboxymethylcellulose and a combination of these two gums (50:50) were used at the rate of 0.5, 1 and 1.5 percent based on the weight of the dry matter of the dough. The doughnut dough was prepared and molded. The fermentation was carried out for 30 minutes under similar industrial conditions (40°C and 40% humidity). Then the frying process at 180°C, icing and packaging were performed, respectively. The moisture content of the dough and doughnuts, the oil uptake of doughnut, density, color and the porosity ratio of the samples were measured. Also, the qualitative characteristics of shelf life, including soft tissue assessment, non-absorption of icing and non-growth of mold were investigated within 14 days. Statistical analysis was performed in a completely randomized design (p<0.05). Results and Discussion: The results showed that, the moisture content of the samples always increased with elevating the percentage of hydrocolloid compounds. Oil absorption decreased with increasing gum percentage and the lowest oil content was observed in the samples containing xanthan gum. Unlike xanthan, the density decreased and the volume increased with elevating the percentage of carboxymethylcellulose gum. Therefore, the highest porosity and softness of the tissue were found in samples containing carboxymethylcellulose. The brightness parameter (L*) was higher in samples containing xanthan, which could be due to the higher moisture content. The red parameter (a*) was also higher in the samples containing xanthan, which due to the higher compression of the product, a relatively more red pigment was observed with increasing xanthan level. The yellowness parameter (b*) in xanthan-containing samples was lower due to reduced oil absorption. The intensity of the color changes (dE) decreased as the percentage of gums increased. Non-absorption of icing was less in hard sample containing xanthan, which could be due to xanthan's competition with gluten in suction of surface water. Mold growth was not observed for any treatment. Overall, the best additive ratio of xanthan gum was 0.5% in terms of reduced oil absorption. Also, the use of carboxymethylcellulose at the level of 0.5% alone could improve the softening of the product texture and made the doughnut with larger volume. Simultaneous use of xanthan gum and carboxymethylcellulose showed behavior under effect of xanthan gum.In general, xanthan gum was more effective than carboxymethylcellulose gum in reducing oil uptake and moisture retention at test levels. Xanthan has shown the greatest reduction in oil absorption due to its thermal gelling and thickening properties, as it has a high capacity for water retention when product is in contact with hot oil. Since the xanthan gum is inexpensive, its effects on product volume can be further investigated in research work, along with bulking agents or other hydrocolloid compounds.
Food Technology
Hassan Sabbaghi
Abstract
Introduction: Doughnut is one of the most widely consumed food products in the world due to its suitable organoleptic properties. Today, with the spread of diabetes and lifestyle changes, consumers are paying more attention to the use of sugar-free foods and dietary products. In the bakery products, ...
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Introduction: Doughnut is one of the most widely consumed food products in the world due to its suitable organoleptic properties. Today, with the spread of diabetes and lifestyle changes, consumers are paying more attention to the use of sugar-free foods and dietary products. In the bakery products, sweeteners play an important role in providing moisture, sweetening, texture formation and increasing the shelf life of the final product. Sweeteners intended to replace sucrose should be water-soluble, with enough flavor, and cost-effective. Also, these compounds must also comply with national and international law. Stevia, which is composed of steviol and glycosides, is resistant to heat and pH and is not fermentable. Therefore, its amount should be chosen in such a way that it has no effect on cooking. In contrast, sweeteners containing dextrose and maltodextrin are also heat-resistant and can affect cooking and maintain the quality properties of fermentation. In order to use stevia in products as a substitute for sugar to maintain the formulation ratios, the fillers including low-calorie sweeteners such as erythritol and maltodextrin should be used. Therefore, in this study, the feasibility of producing sugar-free doughnuts as a dietary product was studied using stevia, erythritol and maltodextrin as sugar substitutes. Materials and Methods: The low calorie sweetener blend (stevia, erythritol and maltodextrin) was designed in the first step. It was found that if 46.175 g of stevia and 1997.82 g of erythritol were mixed and homogenized, a mixture would be obtained with sweetness four times higher than sucrose. So, the "sweetener blend" was used for one-fourth of the sugar removal mass and the rest was compensated with filler as maltodextrin. Instead of sugar, this mixture was added with zero ratio (control), 50 (low sugar) and 100% (no sugar) in the formulation of doughnuts and icing. Evaluation of qualitative characteristic including moisture content, oil absorption, density, color and porosity ratio and sensory analysis for doughnuts were performedThe properties of shelf life, including soft tissue assessment, non-absorption of icing and non-growth of mold were also investigated within 14 days. Statistical analysis was performed in a completely randomized design (p < 0.05). Results & discussion: The results showed that replacing 100% sugar in doughnuts was successful in terms of maintaining quality characteristics. The quality properties of doughnuts with 50% replacement (low sugar product) were not desirable. Sugar-free doughnuts had good quality properties (density, porosity, color and shell-life) compared to the control. Replacing the type of sweetener from sucrose to alcohol sugar can increase the moisture level of the product. As the amount of erythritol increased (no sugar sample), the texture became more moist and soft. The oil uptake of sugar-free doughnut did not show significant difference from the control sample and its sensory evaluation was so favorable. Maltodextrin could act as a bulking agent, stabilizer, and thickener agent in a sugar free formulation. Sugar free doughnuts had more brightness (L*) and less redness (a*), and its yellowness (b*) did not show significant difference with the control sample. It can be said that because more air has penetrated in sugar free doughnut the brightness parameter (L*) increased. The use of polyols (erythritol) results in a brighter color in the product, which is due to the lack of participation of polyols in the Millard reaction because they lack a reactive aldehyde group. The early development of the Millard reaction led to changes in hardness. Therefore, replacing reducing sugars with non-reducing compounds such as alcohol sugars in the formulation decreased tissue changes in the direction of hardening. Because of Millard reaction will reduce the sugars available as a plasticizer in the formulation. Sugar free doughnut showed suitable soft tissue during 14 days and indicated that sweetener has an effect on texture because it controls hydration and tends to disperse starch and protein molecules, thus preventing the formation of a continuous mass. No sugar doughnuts showed suitable sensory evaluation about color, taste, smell, texture, and overall acceptance.Therefore, a mixture of no-calorie and low-calorie sweeteners in this study can be used in the preparation of dietary doughnuts.
Mahboubeh Darapoor; Behzad Nasehi; Hassan Barzegar; Hossein Jooyandeh
Abstract
Introduction: By-products have traditionally been used as animal feed and are considered agricultural waste. However, they are rich in fiber and bioactive compounds, and efforts have been made to utilize them as functional ingredients and for the enrichment of food products. On the other hand, the intake ...
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Introduction: By-products have traditionally been used as animal feed and are considered agricultural waste. However, they are rich in fiber and bioactive compounds, and efforts have been made to utilize them as functional ingredients and for the enrichment of food products. On the other hand, the intake of a sufficient amount of dietary fiber can regulate the flow of intestines, prevent and treat diabetes, cardiovascular and intestinal cancers. In this regard, in recent decades, there has been a tendency to seek new sources of dietary fiber and natural antioxidants, such as agricultural byproduct that were considered. In this regard, sugar cane bagasse, which has chemical compounds such as cellulose, hemicellulose, lignin, as well as phenolic compounds, waxes and minerals. Currently, bagasse used to production Cement (Tian et al., 2016), sand and grains (Sales et al., 2010), Chipboard (Garzon-Barrero et al., 2016), enzymes (Bocchini et al., 2005), single proteins (Rodriguez et al., 1992), vanillin (Mathew & Abraham, 2005), succinic acids (Chen et al., 2016), citric acid (Zhoghi et al., 2013), lactic acid (Laopaiboon et al., 2010). Donut is the only wheat industrial product that has a lot of attractive sensory features in spite of its high fat content. Therefore, one of the goals of the researchers in recent years has been finding solutions to improve its quality by reducing the absorption of oil or increasing the health components such as fiber. Therefore, this study was conducted to investigate the possibility of production of functional donuts that enriched with bagasse. Materials and methods: In this study, in order to optimize the formulation of donuts with two varieties of sugarcane bagasse fiber (0-25%), soybean soluble polysaccharide (0-2%) and frying time (2-5 minutes) on the physicochemical characteristics of donuts and sensory properties by using mini-tab software (version 16) and central composite rotatable design (CCRD) was investigated. The mean comparison was performed using Fisher test at 95% probability level. Bagasse were treated according to the method of Gao et al. (2013). Donuts were prepared according to the formulation by Nouri et al., 2017. Ingredients used in control donut formulation were consisted of 100 g of wheat flour (9 g/100g proteins, (Arde jonob Co., Khuzestan, Iran), 38 g of water, 9g of Shortening (Behshahr Industrial Co., Tehran, Iran), 13g of Egg, 13g of water for yeast, 6.3g of sugar, 6.3g of nonfat dried milk powder (Pegah Co., khozestan, Iran), 3g of active dried yeast (Nabmayeh, Khozestan, Iran), 1.6g of Vanilla extract (AbyazChimieEssence and Colour Co., Tehran, Iran), 1.6g of baking powder (Soheil Powder, Tehran, Iran), and 1.6g of Salt. The volume of the donuts was determined using the rapeseed displacement AACC method 10-05 (AACC, 2000). Moisture content of donuts crumb was measured using a Heraeus oven (model UT 5042, Germany) at 105 ºC for 3.5 h (Kim et al., 2015). The fat content of dried donuts was determined by Soxhlet extraction with petroleum ether for 5 h (Melito & Farkas, 2012). Firmness and springiness were measured in triplicate using a TA.XT2i Texture Analyzer (Stable Micro Systems, Goldalming, UK). The donuts were evaluated for over all acceptance of based on a five-point hedonic scale. The scale of values ranged from “dislike extremely” (score 1) to “like extremely” (score 5). And lightness was evaluated with Konica Minolta colorimeter. Results and discussion: The results showed that most of the proposed models in this study were proportional and meaningful from R2 and R2 (Adj). Also, the lack of fit these model were meaningless and their coefficient of variation was also appropriate. So, bagasse fiber increased moisture, hardness, cohesiveness and gumminess, fat, crust and crumb a, fiber and decreased specific volume, crust L. Increasing frying time increases hardness, cohesiveness, gumminess, and decreases crust L and moisture. Soybean soluble polysaccharide had no significant effect on these cases. According to the panelists, donuts containing bagasse fiber were harder and less chewable and had a darker color than the control sample. Response surface methodology described that donuts with optimum formulation of 9.09% bagasse fiber and 0.78% soybean soluble polysaccharide and the frying time of 2 minutes and 36 seconds would be the most desirable sample that has acceptable consumer characteristics. Investigating the optimal sample composition showed that iron and zinc mineral elements, fiber, fat, and total acceptance were higher than the control sample. However, no significant difference was observed in the control and optimum sample protein content. Also, with increasing durability, the moisture content of the product decreases. On the other hand, the specific volume of the control sample during the days of storage did not have a significant difference at 5% level. While the optimum sample volume in the days of shelf life has decreased. There was no significant difference between the control and optimum sample peroxidase in the first and third days, while on the fifth day, both were significantly decreased. The examination of texture characteristics suggests that the donut crumb of controlled and optimized was harder during the storage period, while the optimum sample was softer than the control sample.
Sepideh Aryaee Majd; Mania Salehifar
Abstract
Introduction: Donte is one of the most important fermented products in all over the world which similar to bread, after ferret fermentation process, dividing, shaping and rest of the dough, it would be frying in the oil instead of baking in the oven. We feel the need of using food additives (such as ...
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Introduction: Donte is one of the most important fermented products in all over the world which similar to bread, after ferret fermentation process, dividing, shaping and rest of the dough, it would be frying in the oil instead of baking in the oven. We feel the need of using food additives (such as antioxidants, enzymes and etc.) in order to produce such high quality products with long shelf life because of industrialization of donut, large function production and increasing customer demand. The antioxidant compounds causes the food to have long-lasting shelf life and this results in producing a practical product. This research was carried out to evaluate effects of apple extract(in quantities of 8,10,12% ) and pimento extract (in quantities of % 5/1، 5/2، 5/3) as a rich source of Antioxidant affecting the rheological paste properties including the Farinography test, physicochemical properties such as hardness in periods of 1 to 3 days, humidity and color, shelf life index including peroxide in three periods of 1 , 15, and 30 days after cooking, DPPH and total Phenol inhibition tests and sensory evaluation of the product. Effects of the extracts on the rheological dough has shown that apple and pimento influencing the Farinography factors caused. Moreover none of these extracts had a meaningful effect on the index of paste quality. Result of phytochemical evaluation indicated that the hardness in two periods of 1 and 3, color value indicated, peroxide index and total acceptance decreased as the apple and pimento increased. The humidity content increased as the apple and pimento were used more. The result of DPPH and total Phenol inhibition tests showed that the pepper extract in DPPH free radical control was more successful than apple extract, and the amount of phenolic compounds in pepper extract was 2.4 more than apple extract. All experiments were replicated three times Optimized conditions included the use of 11.95% apple extract and 3. 3% sweet pepper extract in donut dough formulation. Generally addition of plant extracts can decrease oxidation speed of donut effectively.
Materials and methods: Include procedures and method of producing donut and methods of extracting apple and pimento also include test to measure flour such as moisture, ash, acidity, pH and protein and moisture, hardness, color, peroxide index, farinografy test, Total phenol and DPPH free radical inhibitory. The statistical population includes different levels of apple and pimento extracts, measured parameters have been studied by using simple line and polynomial equations 2 and 3.After testing in research methodology and data extraction, data analysis was carried out using RSM method and Design Expert 8 and statistical significance was set at (p<0.05) All results have been made 3 times, on average.
Results & Discussion: The effects of the extracts on the rheological dough has shown that apple and pimento influencing the Farinography factors caused an increase in water absorption, and pimento reduced the stability, development time and increased the degree of softening. Moreover none of these extracts had a meaningful effect on the index of paste quality. It should be mentioned that the aforementioned effects are more influenced by the apple extract Result of phytochemical evaluation indicated that the hardness in two periods of 1 and 3 decreased as the apple and pimento increased. The humidity content increased as the apple and pimento were used more. The result of low light color value indicated that L* decreased by increasing apple and pimento extracts, which this had no impact on a* and b* color indexes. The result of shelf life tests showed that by increasing the amount of apple and pimento extracts in donut samples in two periods of 5 and 30 days caused decrease peroxide index and The result of DPPH and total Phenol inhibition tests showed that the pepper extract in DPPH free radical control was more successful than apple extract, and the amount of phenolic compounds in pepper extract was 2.4 more than apple extract. The sensory evaluation results showed that the increase in apple and pimento caused reduction in total acceptance of the produced. All experiments were replicated three times Optimized conditions included the use of 11.95% apple extract and 3. 3% sweet pepper extract in donut dough formulation. Generally addition of plant extracts can decrease oxidation speed of donut effectively.
Mahin Heydari Ashkezari; Mania Salehifar
Abstract
Introduction: One of the useful methods to increase the roasted product’s durability is the addition of antioxidants. The antioxidants can replace the synthetic antioxidant in doughnut. One of the problems related to doughnut is oxidative corruption in industrial type. The purpose of this study was ...
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Introduction: One of the useful methods to increase the roasted product’s durability is the addition of antioxidants. The antioxidants can replace the synthetic antioxidant in doughnut. One of the problems related to doughnut is oxidative corruption in industrial type. The purpose of this study was to extract pomegranate flower extraction and use of vitamin B3 as two natural antioxidants in doughnuts.
Materials and methods: In this study, the effect of three variation such as pomegranate flower extraction (0.07, 0.55 and 0.04 percent), vitamin B3 (1.5, 1.9 and 2.3 percent) on oxidation features (peroxide index, acidity, anisidine, totox and Thiobarbituric acid), tissue obstruction and sensory evaluation (taste, tissue, color, scent and total acceptance) were evaluated and analyzed in the research. The mean comparison of examined samples was carried out using RSM method and central cube design (CCD).
Results & discussion: The obtained results showed that adding pomegranate flower extraction and vitamin B3 to doughnut caused significant decrement of peroxide index, anisidine, totox, acidity and Thiobarbituric acid in 15th day. While tissue stiffness increased with increasing vitamin B3 on the 15th day. The sensory evaluation also expressed that increasing pomegranate flower extract’s percentage and vitamin B3 decreased total acceptability in all sensory features. Results of optimization showed the doughnut samples containing 0.07% pomegranate flower extraction and 1.97% vitamin B3 were accepted as the closest samples to the control sample and as the foremost treatment from sensory and durability point of view.
Mehran Nouri; Behzad Nasehi; Vahid Samavati; Saman Abdanan
Abstract
Introduction: Fried foods such as donuts enjoyed worldwide for their taste, distinctive flavor, aroma and crunchy texture. There is, however, grave health concern over large fat content of fried foods (Melito and Farkas, 2013). There are several ways to lower fat content in deep-fried foods. One method ...
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Introduction: Fried foods such as donuts enjoyed worldwide for their taste, distinctive flavor, aroma and crunchy texture. There is, however, grave health concern over large fat content of fried foods (Melito and Farkas, 2013). There are several ways to lower fat content in deep-fried foods. One method is to reformulate the product by adding hydrophilic ingredients such as dietary fibers to reduce oil uptake during frying. Another method to reduce fat content is to partially cook the food using another heating method (Melito and Farkas, 2012). There is an increasing interest in microwaving foods for several reasons: it is faster than conventional methods, the energy consumption is often lower and foods cooked by microwaving maintain nutritional integrity.vIn foods, the appearance is a main criterion in making purchasing decisions. Appearance is used throughout the production –storage-marketing-utilization chain as the key means of judging the quality of individual units of product. The appearance of unities of products could be assessed by considering their color and surface texture. The use of computer-vision technology has quickly increased in the fields of quality inspection, classification and evaluation in processing a large number of food products (Brosnan and Sun, 2004). Therefore the aim of this study was to study the effects of microwave pre-treatment on sensory and appearance properties of donut.
Materials and methods: Response surface methodology and Box- Behnken design were applied to evaluate the effects of independent variable include microwave power (300-900 W), microwave time (30-90 s) and frying time (70-130 s) on sensory and appearance properties of donuts. Donuts were prepared according to the formulation by Melito and Farkas (2012) with some modifications. Ingredients used in donuts formulation were consisted of 100 g of wheat flour (9 g/100g), 52 g of water, 9.75 g of Shortening, 14 g of Egg, 14 g of water for yeast, 6.80 g of sugar, 6.80 g of nonfat dried milk powder, 3.25 g of active dried yeast, 1.70 g of Vanilla extract, 1.7 g of baking powder, 1.70 g of Salt, 1.3 g of Persian gum and 7.00 g of carrot pomace powder. The dough was cut into squares approximately 50 mm on each side. Then, the dough pieces were allowed to proof for 30 min at 27 ºC. The proofed samples were pre-treated using a microwave oven at different levels of microwave power and microwave time in accordance with the experimental design. Formerly, the per-treated donuts were deep-fat fried in a Moulinex deep-fat fryer (model F18-RA, France) filled with 1.5 L of vegetable frying oil (A mixture of Sunflower, palm, and soybean oil; Behshahr CO., Tehran, Iran) at different levels of frying time in accordance with the experimental design. The oil was preheated for 30 min prior to frying and replaced with fresh oil after every frying process. After frying, donuts were removed from the fryer and allowed to cool for 30 min on paper towels. They were then stored in coded sealed polyethylene bags.The evaluation of the crumb grain and crust color of donuts was performed using an image analysis system consisted of a Canon digital camera (model SX60 HS, Japan) and a personal computer with a Pentium(R) Dual-Core processor and Windows 7 Ultimate. The samples were photographed at a fixed distance of 30 cm from the crumb of samples, which were sitting inside a black box. The captured images were analyzed using the MATLAB R2014a software (The MathWorks Inc., Natick, Mass, USA).The CIE L*a*b* (or CIELAB) color model was used for determination of the crust color of donuts. Crumb grain features of the donut samples were obtained with described digital image analysis system. After imaging, each image was converted from RGB format to 8 bits (grey level) using the MATLAB software. In this format, an area of 3 × 3 cm2 was selected at the center of the captured image. After contrast enhancement of image, the image segmented using the Otsu algorithm, which produces highly uniform binary images (Otsu, 1979). Finally, crumb grain properties of donuts were studied by determination of cells densities and area of cells. Sensory evaluation of donut samples was carried out by assigning scores for crust appearance, crumb appearance, crust color, aroma, texture, taste and overall acceptance parameters based on a nine-point hedonic scale. (Stone et al., 2012).
Results and discussion: Results showed that roughness of the donuts surface increased significantly (p
