---

Potato is known as a valuable source of starch which plays an important role in human nutrition. Proper storage conditions should be considered to protect the nutritional properties of potato after drying. The effect of three packaging materials (transparent biaxially oriented polypropylene laminate (BOPP); semitransparent BOPP; polyethylene-polyamide (PE-PA) laminate) in three packaging conditions (vacuum, N2, natural atmosphere) and in two temperature treatments (blanching in hot water; steam) on microwave-dried potato (Solanum tuberosum L.; Solanaceae) cubes was studied. Moisture content and oil absorption decreased in microwave dried potato by increasing storage time from 60 to 120 days. The moisture loss rate in vacuum packed samples in polyethylene polyamide film was less than BOPP. Steam blanched samples not only had more moisture but also absorbed less amount of oil. The dried and packed potatoes under nitrogen atomospher and in transparent BOPP had the highest percentage of oil absorption with 9.75% and 9.87%, respectively. Changes in the internal structure, moisture and gelatinization of starch in the surface are factors affecting the absorption of oil. Blanched samples with steam and vacuum packed in polyethylene polyamide films, have the best results in increasing the shelf-life and reducing oil absorption.

---

 In this research, the effect of microwave pre-treatment on qualitative characteristics and sensory properties of air-dried potato sticks was investigated. Different powers (180-900W) and times (1-5 minutes) of microwave were used before air-drying of samples. The moisture content, rehydration, shrinkage, browning, colour indices and sensory properties (taste, colour, shape, strength, and total acceptance) of potato samples were evaluated after the drying process and the response surface method (RSM) was used to determine the optimal conditions for the microwave ‌ pre-treatment. Used for the highest levels of physicochemical and sensory properties. ‌The results showed that, with increasing the power and time of the microwave oven resulted in an increase in the moisture content, shrinkage, rehydration and total colour change of the samples. Sensory evaluation results showed that in the microwave pre-treatment, only the scores of the taste and colour of potato samples were influenced by the microwave power and time. According to the results of optimization by the surface response method, the power of 180 Watts and the time of 3.5 minutes for the microwave pre-treatment were introduced as optimum conditions.
 

---

Propolis is a resinous substance collected by honeybees from various plant sources. This study was aimed to evaluate antioxidative activities of propolis extract in sunflower oil during the storage period. In this study, the antioxidant capacities of the propolis extracts (ethanol, methanol and aqueous extracts) were determined initially using DPPH and the best extract was selected to add to oil. The results stated that the methanolic extract of propolis had the highest antioxidant activity. Then, different concentrations of methanolic extract (0, 0.5 and 1 percentage) were added to sunflower oil and incubated for 60 days at 25°C. To compare the propolis extract with synthetic antioxidants, commercial sunflower oil containing TBHQ was prepared and incubated, too. Peroxide values (PV), acidity index and thiobarbituric acid-reactive substances (TBARS) levels were measured every 20 days during the period of the study. The abtained data were analysed using completely randomized design. Results showed that the addition of antioxidant to sunflower oil lead to decrease of PV, TBARS and acidity values of samples. In this respect, 1% methanolic extract of propolis was more potent than the 0.5% extracts and synthetic Antioxidant. During storage, the amounts of oxidative indexes of samples were increased gradually. The highest amount of oxidation was observed for crude oil. The sensory results showed no significant different between flavor, color, and overall acceptance scores of oil with propolis extract and commercial Sunflower oil, but the score of odor of oil with propolis extract was lower than the commercial oil. It seems that methanolic extract of propolis is a potent antioxidant, which makes it a potential antioxidant for oil and oily products during storage.

 

---

Formulation of an edible coating based on gum tragacanth and chitosan was optimized for fresh apricots by Response Surface Methodology (RSM). The effects of the concentration of gum tragacanth and chitosan (independent variables) on soluble solids content, weight loss, titratable acidity, pH, reducing sugar, moisture content, and firmness (response variables) were studied. The results showed that the obtained RSM models were fitted for all response variables, except for soluble solids content and titratable acidity. Gum tragacanth and chitosan treatments significantly decreased the weight loss of the apricots during storage. The firmness of apricots was increased at higher concentrations of gum tragacanth. The pH of the apricots was lower at lower concentrations of gum tragacanth and chitosan. This work showed that the coating could improve apricot firmness and stability in terms of weight loss, pH, and moisture content during storage, and increase the commercial value of the product. To meet the desirable properties, the ideal concentrations of gum tragacanth and chitosan in the coating were 1.02 and 0.33% (w/v), respectively.