نشریه فرآوری و نگهداری مواد غذایی
سال چهارم شماره 2 (پیاپی 12، پاییز و زمستان 1391)

Osmo-dehydofreezing is a combined process consisting of osmotic dehydrationfollowed by air dehydration and then freezing. Osmodehydro freezing is anadvances method with osmodrying and freezing of fruits and vegetables.Purpose of This study is the production of products with high shelf life properties.In this study plums samples after peeling were dipped in solutions contain ofsucrose, ascorbic acid and citric acid with different percentage. Then the moisturewas reduced under 65°C hot air up to 38%. The samples immediately were freezedin-40°C after cooling in 4-5°C and stored in -20°C. Osmodehydrated productewere analyzed for aw, PH, sugar, ascorbic acid with spectroscopic methodand organoleptic test, after defrost in 20 degree centigrade during 80 days, 20 daysinterval. Statistical analysis of data was done in randomized plan (P<0.05) andResults showed the best samples content for those samples treated in 0.1 percentascorbic acid and dipped in 40% sucrose solution.

Carrot contains valuable and healthy material. Beta carotene pigments and antioxidants on it are so effective against free radicals in body. Formulation of novel fruity products is object of some investigations and in parallel of it, have been used different compositions of hydrocolloids and others additional material in its formulations. In addition we can use the low edible quality of carrots or surplus one. In this study, effects of starch (0, 2 and 4%) and guar (0.5, 1 and 2%) on sensory properties, textural parameters and color parameters of carrot pastille were evaluated. Results showed that different concentrations of independent variables on hardness, adhesivness, springiness and mean of L*, a*, b* and also overall acceptance were significant (P<0.05). Results of PCA illustrated that effective textural parameters on overall acceptance of carrot pastille were hardness, cohesiveness and chewiness.

Green tea extract is rich of antioxidant. These antioxidants can replace the synthic antioxidant in doughnut. For this purpose extracted antioxidant of green tea and used as natural antioxidant in doughnut. Aim this proposal reduce synethic antioxidant. with respect to notice the synergistic properties between green tea extract and organic acids (acid ascorbic), acid ascorbic was added in 4 levels (0, 50, 150, 200) ppm and green tea extract was added in 4 levels (0,100,150,200) ppm green tea to doughnut while addition of ascorbic acid showed no significant effect on the production of peroxide value, green tea extract decrease moisture content and peroxide value. besides, ascorbic acide increase crumb colour and appearance, and decrease odor and general acceptance, while green tea extract increase odor, flavor general acceptance crumb colour. There is significant similorition between nature antioxidant and synetic antioxidant properties.

Bruising damage caused by impact form the main part of all kinds of mechanical damages after harvesting fruits. The prediction of bruise volume is essential for the applicability of the discrete element method to simulate bruise damage during fruit transport and handling. Bruise prediction models can provide useful information about the influence of fruit factors (e.g. ripeness) on bruise susceptibility, leading to recommendations for fruit handling. Bruise prediction models were constructed for the Golden Delicious apple. Bruise volume was used as a measure for apple bruising. The purpose of this research was to evaluate RBF artificial neural network capability in predicting apple bruise volume. The study was conduct using empirical data on 120 apples. Optimal parameters for the RBF neural network were select via a trial and error procedure on the available data. In order to evaluate the performance of the RBF model in the prediction of apple bruise volume, some statistical tests, such as comparisions of the means, variance, statistical distribution as well as linear regression were used between the actual data and the prediction data using RBF neural network. Results showed that in training phase and test phase P-value was greater than 0.9, indicating that there was no significant difference between statsitcal parameters such as average, variance, statistical distribution. This results suggest that RBF neural network can learn bruise volume model very well. Results showed that the predicted values and actual values of apple bruise volume fitted very well (R2 > 0.9), with mean absolute percentage error (MAPE) less than 2.82%. There was no significant difference between the actual values obtained from apple bruise volume and predicted value calculated by models. Also the results reaveled that the model established by RBF was more accurate than regression model to predict apple bruise volume.

The aim of this study was to compare the effects of olive leaf extracts and synthetic antioxidant BHT at Concentration of 1% at increase the shelf life of rainbow trout fillets in light salted and packed at 4±1 °C that Index of peroxide (PV), free fatty acids (FFA), Thiobarbituric acid (TBA), Humidity, pH and sensory evaluation of fillets of rainbow trout kept in the refrigerator at the time of Zero, 3, 6, 9, 12 and 15 were measured. Based on the statistical results, PV was in all treatments significantly over time decline (P<0.05), Also TBA and FFA values over time in all treatments significantly increased (P<0.05) but TBA, PV and FFA of antioxidant samples compared with control samples was significantly at all times to lower (P<0.05). Also Methanol extracts olive leaves at 1% as good as control the peroxide value and thiobarbituric acid and replace synthetic antioxidants is such as Butylated hydroxytoluene at level 100 ppm. According to the results of organoleptic test and no significant difference between both antioxidants can advised be use types of antioxidants to keep the fish. According to the results the research olive leaf extract had more efficiency on increasing of shelf life, smell, texture of the fish fillets.

Drying foodstuffs can have negative effects on quantitative and qualitative characteristics of the products, including porosity and bulk density. Therefore,novel technologies can be used to improve these characteristics. In this study, apparent density changes during drying grapes pretreated with ultrasound for 10, 20 and 30 minutes, and carboxymethyl cellulose (CMC) at three concentrations of 0.1, 0.2 and 0.3 percent was evaluated. In order to dry the grapes, a tunnel dryer was used and the samples apparent density was calculated during drying. The results showed that apparent density of the grape samples is increased with increasing ultrasound time and decreasing CMC concentration. Furthermore, apparent density was modeled through existing models in the literature as well as the models proposed in this study. One of the proposed models (Model 6, Table 2) was selected as the most appropriate model to predict changes in the apparent density of the grapes during drying.

Combination method took place with quality tests of dried samples. The drying data of parsley with hot air and microwave methods was fitted with eight models: Page, Newton, Henderson and Pabis, Logarithmic, Midilli et al., Two-term exponential, Verma et al. and Wang and singh. Results showed that page model have the best description for drying belongs of parsley. The checking the combination process and the qualitative testing of the final product showed that using of the microwave energy as the final drying process leads to many different and favorable aspects. This method can significantly improve the quality parameters such as color, rehydration and the amount of vitamin C and also it reduces the drying time of parsley. Longest drying time of parsley was in drying with hot air at 50 ºc that which lasted 420 minutes. This time in combination drying process in order was reduce the 43.66% in drying time of parsley than drying with hot air in 50 ºc.