Food Engineering
Moein Inanloodoghouz; Fakhreddin Salehi; Mostafa Karami; Ashraf Gohari Ardabili
Abstract
IntroductionFruits have a limited harvest season, and the amount of their waste is significant. Drying extends the shelf life of food, and the infrared dryer reduces the time and cost of the drying process. In this study, the effect of sonication at different powers and temperatures along with edible ...
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IntroductionFruits have a limited harvest season, and the amount of their waste is significant. Drying extends the shelf life of food, and the infrared dryer reduces the time and cost of the drying process. In this study, the effect of sonication at different powers and temperatures along with edible coating with xanthan and wild sage seed gums on the drying process of cornelian cherry by an infrared dryer was investigated. Materials and MethodsSolutions of xanthan and wild sage seed gums were used for coating of fresh cornelian cherry. Xanthan gum powder (food grade) was purchased from FuFeng Co. (China). Wild sage seed gum was extracted and used in powder form after drying and grinding to prepare the gum solution. In this study, various concentration of gums solutions (xanthan and wild sage seed) were first prepared in a graduated glass beaker and placed in an ultrasonic bath (Backer vCLEAN1-L6, Iran). The fruits were immersed in the gum solutions (inside the beakers) and sonicated for 5 min (40 kH). Infrared dryer with an infrared radiation source (250 W, near-infrared (NIR), Noor Lamp Company, Iran) was used for drying samples. The distance of samples from the radiation lamp was 10 cm. After each pretreatment (sonication and coating), the samples were dried, until reaching a constant weight. The mass changes of samples were recorded using a Lutron GM-300p digital balance (Taiwan). The rehydration tests were conducted with a water bath (R.J42, Pars Azma Co., Iran). Dried samples were weighed and immersed for 30 minutes in distillated water in a 200 ml glass beaker at 50°C. Then, the extra moisture was drained for 30 s and the samples were re-weighed. The rehydration ratio values (%) of dried samples were determined as the ratio of the final weight of rehydrated samples over the dried samples weight × 100. The color of the cornelian cherry was calculated by determining the lightness (L*) and chromaticity (redness (a*) and yellowness (b*)), and was measured using a scanner (Hp Scanjet 300, China) and Image J software (V.1.42e, USA). The Folin-Ciocalteu (Folin-Ciocalteu's phenolics reagent, Sigma-Aldrich, USA) method was followed for measuring the total phenolics content of dried cornelian cherry. The absorbance of samples (765 nm, UV-VIS spectrophotometer, XD-7500, Lovibond, Germany) was compared with the Gallic acid standard curve. The results were expressed as mg GAE/g dry matter. Effect of applied power by the ultrasonic device at three levels of 0, 75, and 150 W and the effect of temperature at three levels of 20°C, 40°C, and 60°C on the rehydration and total color difference index of dried cornelian cherry were investigated. Also, the effect of coating with xanthan and wild sage seed gums on preserving phenolic compounds, antioxidant activity, and sensory properties of the product was evaluated. Results and DiscussionThe average drying time of uncoated cornelian cherry, coated with xanthan gum, and wild sage gum was 62 min, 48.7 min, and 48.4 min, respectively. The examined treatments in this research did not have a significant effect on rehydration change of the dried product. Ultrasonic pretreatment at both 75 and 150 W powers had a decreasing effect on the color changes, which indicates improvement of color and prevention of color change and decrease in desirability. The effect of coating on color changes was also investigated, and the amount of color changes in the uncoated, coated with xanthan gum and wild sage seed gum samples was equal to 26.71, 26.02, and 31.36, and there was no significant difference between them (p>0.05). Using wild sage seed gum preserved more of phenolic and antioxidant compounds. The total phenolics content of fresh cornelian cherry, and dried samples including market, without coating, coated with xanthan gum, and coated with wild sage seed gum was 23.0, 4.7, 0.8, 9.8, and 12.1 mg gallic acid/g, respectively. The market sample had a significant difference with other dried samples dried by infrared (p<0.05). The sample from the market had the least DPPH radical scavenging activity (p<0.05). The market sample scored as the lowest sensory evaluation and had a significant difference with all samples in all sensory attributes (p<0.05). ConclusionFrom the panelist’s point of view, the sample coated with wild sage seed gum was the best sample, and the highest score for sensory parameters and overall acceptance was associated with this sample.
Enayat-Allah Naghavi; Sadegh Rigi
Abstract
Lemon verbena leave is a flavoring food additive as well as a good source of valuable compounds such as essential oils, flavonoids and phenolic acids. However, similar to many other aromatic plants, lemon verbena leave is perishable due to its high moisture content. The aim of this work was to study ...
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Lemon verbena leave is a flavoring food additive as well as a good source of valuable compounds such as essential oils, flavonoids and phenolic acids. However, similar to many other aromatic plants, lemon verbena leave is perishable due to its high moisture content. The aim of this work was to study the effect of air temperature (45, 55, and 65°C) on the quality attributes of lemon verbena leaves during hot-air drying (HAD). The drying kinetics were also modeled. The results showed that higher drying temperature led to a significant decrease (p˂0.05) in the rehydration ratio due to a change in the structural features of the dried leaves. The essential oil content of dried samples was also significantly different (p˂0.05) from that of the fresh leaves due to high loss of volatile components and ranged from 0.42 to 0.85. Moreover, a significant increase in the value of effective moisture diffusivity (Deff) and color change was observed when the samples were dried at 65°C compared to 45°C. The value of Deff varied from 1.140×10-10 to 2.280×10-9 m2/s and the activation energy was found to be 31.04 kJ/mol. The greatest R2 (≥0.999) and the lowest RMSE and SSE were obtained for the Naghavi et al. model (proposed in this research)
Arash Ghaitaranpour; Masoud Taghizadeh; Hamed Mahdavian Mehr; Mohammad Reza Abdollahi Moghaddam
Abstract
Bezhi (or Beji) is a special sweet and fried cookie which is produced traditionally in west region of Iran. In this study, the effect of different temperature levels (150, 165 and 180°C) and frying time (1 to 8 min) on physicochemical properties of Bezhi was investigated. The obtained results showed ...
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Bezhi (or Beji) is a special sweet and fried cookie which is produced traditionally in west region of Iran. In this study, the effect of different temperature levels (150, 165 and 180°C) and frying time (1 to 8 min) on physicochemical properties of Bezhi was investigated. The obtained results showed that increasing frying time up to the first 3 minutes causes a significant increase in sample volume. Although, further increase in frying time was not accompanied by volume increase but the mean volume was decreased significantly. Generally any increase in the studied parameters (temperature and frying time) would increase the samples’ diameter while other dimensional characteristics remained unchanged. Moreover, increasing temperature and frying time would increase the samples’ hardness as well as their color changes (∆E). L* value showed decrease when increasing studied parameters. The rate of decrease in L* in the studied temperature levels (150, 165 and 180 °C) were found to be 0.00987, 0.07665 and 0.11250 S-1 respectively. In addition a* value was increased by increasing the studied parameters while b* remained unchanged. The activation energy for the enzymatic reactions in Bezhi samples was 31.12 Kcal/mole which demonstrates the high effect of temperature on these reactions in the studied temperature range. Temperature and frying time showed considerable effect on the crust formation of samples. While the maximum crust thickness at 150 °C was reached to 0.55 mm, the value of 1.45 mm was recorded as the maximum crust thickness at 165 and 180 °C. So oil temperature and frying time have an important effect on physiochemical properties of Bezhi.
