جستجوی مقالات مرتبط با کلیدواژه "carrot juice" در نشریات گروه "صنایع غذایی"

Carrot juice color changes from orange to brown immediately after production. Blanching is a suitable way to preserve and commercialize this product. In this study, an ohmic device was used as a heating source, and polyphenol oxidase enzyme was selected as an indicator of enzyme inactivation sufficiency to color change of carrot juice. Fresh carrot juice was subjected to thermal processing under 3 temperature levels of 70, 80, and 90 degrees of Celsius and 4 time levels of 0, 20, 40 and 60 seconds with a constant voltage of 100 volts and the enzyme inactivation, Brix, pH and color indexes L* , a* and b* were checked. Constant values of reaction rate, activation energy, D-value and Q10   were investigated. The kinetics of inactivation of polyphenol oxidase of carrot juice samples were calculated at 70, 80 and 90 degrees of Celsius. The changes of enzyme inactivation, Brix, pH and a* parameter with increasing temperature and time were significant at 1% probability level by completely random design. The level of enzyme inactivation was also measured by the conventional water bath method and compared with the ohmic method, and the results indicated the greater efficiency of the ohmic method. As the temperature increased, the Brix level increased and the color of carrot juice changed from orange-yellow to orange-red (p≤0.05).

In recent years, researches have proven to be promising for specifying and confirming the potential benefits of using probiotic and prebiotics in dairy products and beverages. The combination of probiotics and prebiotics which have synergistic effect is called ymbiotic. The aim of this study was to produce ymbiotic carrot juice. To achieve this goal, carrot juice samples containing 2% inulin as a prebiotic substance was pasteurized at 90 °C for 4 minutes and fermented at 30 °C by adding two probiotic bacteria Lactobacillus casei and Lactobacillus plantarum, both individually and in combination. Probiotic bacterial count, pH, acidity, brix, viscosity tests during 45 days of storage and sensory evaluation on the seventh day were performed. The results showed the significant effect of bacterial type and time on the viability of probiotic bacteria, pH, acidity and brix of the samples (P <0.05). The samples containing the combination of two probiotic bacteria had a higher number of bacteria (14.49 ± 0.38 log cfu/ml) and the number of probiotic bacteria decreased over time. With increasing time, the pH of all samples decreased, which was more evident in Lactobacillus casei, but the acidity of them increased (P <0.05). The brix of combined bacteria samples was lower than others while the effect of the bacterial species on the viscosity of samples was not significant (P>0.05). Over time, brix and viscosity showed a decreasing trend. The effect of bacterial type and their application on sensory properties was not significant (P> 0.05). In general, ymbiotic carrot juice containing the combination of two mentioned probiotic bacteria with maximum survival of probiotic bacteria (≥107 ) and maintaining other chemical, physical and sensory properties was proposed as a functional product for use in consumer diets.

Ohmic heating, also known as Joule heating, is an electric heating method for food products. Ohmic heating is an advanced heating process in which foods act as electrical resistances. Its laboratory system usually involves electrodes that are in contact with food, whereby electricity is transmitted through the foodstuff by a voltage change. In this research, the effect of ohmic heating on the specific energy consumption, total color change (ΔE) and percentage of pH change of carrot juice in different voltage gradients (15, 20 and 25V/cm) using different electrodes (steel, copper, aluminum and zinc) were investigated. The results showed that with increasing the voltage gradient, the special energy consumption decreased. The copper electrode has the best performance in percentage of pH change, specific energy consumption and total color change (ΔE). The specific energy consumption was changed from 3.45 to 3.87 MJ/kg for the copper electrode on gradient of 25V/cm and the steel electrode on voltage gradient of 15V/cm, respectively. Ohmic heating, also known as Joule heating, is an electric heating method for food products. Ohmic heating is an advanced heating process in which foods act as electrical resistances. Its laboratory system usually involves electrodes that are in contact with food, whereby electricity is transmitted through the foodstuff by a voltage change. In this research, the effect of ohmic heating on the specific energy consumption, total color change (ΔE) and percentage of pH change of carrot juice in different voltage gradients (15, 20 and 25V/cm) using different electrodes (steel, copper, aluminum and zinc) were investigated. The results showed that with increasing the voltage gradient, the special energy consumption decreased. The copper electrode has the best performance in percentage of pH change, specific energy consumption and total color change (ΔE). The specific energy consumption was changed from 3.45 to 3.87 MJ/kg for the copper electrode on gradient of 25V/cm and the steel electrode on voltage gradient of 15V/cm, respectively. Ohmic heating, also known as Joule heating, is an electric heating method for food products. Ohmic heating is an advanced heating process in which foods act as electrical resistances. Its laboratory system usually involves electrodes that are in contact with food, whereby electricity is transmitted through the foodstuff by a voltage change. In this research, the effect of ohmic heating on the specific energy consumption, total color change (ΔE) and percentage of pH change of carrot juice in different voltage gradients (15, 20 and 25V/cm) using different electrodes (steel, copper, aluminum and zinc) were investigated. The results showed that with increasing the voltage gradient, the special energy consumption decreased. The copper electrode has the best performance in percentage of pH change, specific energy consumption and total color change (ΔE). The specific energy consumption was changed from 3.45 to 3.87 MJ/kg for the copper electrode on gradient of 25V/cm and the steel electrode on voltage gradient of 15V/cm, respectively. Ohmic heating, also known as Joule heating, is an electric heating method for food products. Ohmic heating is an advanced heating process in which foods act as electrical resistances. Its laboratory system usually involves electrodes that are in contact with food, whereby electricity is transmitted through the foodstuff by a voltage change. In this research, the effect of ohmic heating on the specific energy consumption, total color change (ΔE) and percentage of pH change of carrot juice in different voltage gradients (15, 20 and 25V/cm) using different electrodes (steel, copper, aluminum and zinc) were investigated. The results showed that with increasing the voltage gradient, the special energy consumption decreased. The copper electrode has the best performance in percentage of pH change, specific energy consumption and total color change (ΔE). The specific energy consumption was changed from 3.45 to 3.87 MJ/kg for the copper electrode on gradient of 25V/cm and the steel electrode on voltage gradient of 15V/cm, respectively. Ohmic heating, also known as Joule heating, is an electric heating method for food products. Ohmic heating is an advanced heating process in which foods act as electrical resistances. Its laboratory system usually involves electrodes that are in contact with food, whereby electricity is transmitted through the foodstuff by a voltage change. In this research, the effect of ohmic heating on the specific energy consumption, total color change (ΔE) and percentage of pH change of carrot juice in different voltage gradients (15, 20 and 25V/cm) using different electrodes (steel, copper, aluminum and zinc) were investigated. The results showed that with increasing the voltage gradient, the special energy consumption decreased. The copper electrode has the best performance in percentage of pH change, specific energy consumption and total color change (ΔE). The specific energy consumption was changed from 3.45 to 3.87 MJ/kg for the copper electrode on gradient of 25V/cm and the steel electrode on voltage gradient of 15V/cm, respectively. Ohmic heating, also known as Joule heating, is an electric heating method for food products. Ohmic heating is an advanced heating process in which foods act as electrical resistances. Its laboratory system usually involves electrodes that are in contact with food, whereby electricity is transmitted through the foodstuff by a voltage change. In this research, the effect of ohmic heating on the specific energy consumption, total color change (ΔE) and percentage of pH change of carrot juice in different voltage gradients (15, 20 and 25V/cm) using different electrodes (steel, copper, aluminum and zinc) were investigated. The results showed that with increasing the voltage gradient, the special energy consumption decreased. The copper electrode has the best performance in percentage of pH change, specific energy consumption and total color change (ΔE). The specific energy consumption was changed from 3.45 to 3.87 MJ/kg for the copper electrode on gradient of 25V/cm and the steel electrode on voltage gradient of 15V/cm, respectively.

Heat pasteurization has undesirable effects on nutrients and nutritional value of food. Ultrasound technique is used to degrade microorganisms and enzyme inactivation that increases products shelf-life without change in nutritional properties. In this regard, this study aims to produce synbiotic carrot juice containing 2% w/w inulin as a prebiotic substance and two probiotic bacteria, Lactobacillus casei and Lactobacillus plantarum using two different treatment

thermal (90°C for 4 minutes) and sonication (60°C and 37 kHz for 10 minutes). Probiotic bacteria count and viability, pH, acidity, brix, viscosity and sensory properties were evaluated during 45 day storage time. The results showed a significant effect of the type of processing method and storage time on the probiotic bacteria count, pH, acidity and brix of samples. The effect of the processing method on viscosity was not significant while, viscosity and brix of the samples reduced during storage time. The results also indicated that thermal method reduced the overall acceptability of synbiotic carrot juices. Considering the degradation effects of heat, synbiotic carrot juice treated by ultrasound with maximum survival of probiotic bacteria, acceptable chemical and physical properties and high organoleptic scores was suggested as a functional product.

The aim of the research was to study the effect of pasteurization temperature, storage time and carrot juice ratios on pasteurized cow milk enriched with carrot juice. For this purpose, after carrot juice extraction and filtration, different ratio of carrot juice (10, 20, 30, 40 and 50 %) were added to pasteurized cow milk and mixed properly. Then samples were filled in glass bottles and pasteurized at different temperatures (65, 70 and 75 °C) for 30 min. The samples were quickly cooled and stored at 4 °C up to 13 days. The bioactive compounds (total carotenoids (ß-carotene equivalent), total phenols (Gallic Acid equivalent) and vitamin C) and were analyzed during storage time (1, 4, 7, 10 and 13th). The results showed that the carotenoid, vitamin C and total phenol content of milk carrot drinking were increased by increase of carrot juice ratio. Furthermore, higher pasteurization temperature resulted in higher loss of carotenoids, total phenols and vitamin C in samples. Also, during storage time, the amount of carotenoids, total phenols and vitamin C in samples were decreased due to oxidation, deformation or interaction with other compounds. Stability and phase separation test of samples showed that all of treatments are stable during storage time. The results showed that increase of carrot juice and pasteurization temperature resulted in increase and decrease of bioactive compounds respectively and proper shelf-life of milk-carrot drinking samples were 10 days.

Probiotics have several advantages for human health. Since most of the probiotic foods are dairy products, they cannot be consumed by humans who are allergic to milk proteins or have severe lactose intolerance. While looking for alternative food matrices, the suitability of carrot juice as a raw material for the production of probiotic food with Lactococcus strain (L. lactis) isolated from local cheese was investigated. Pasteurization of freshly prepared carrot juice at 85°C for 5 min decreased the microbial population and enzymes are disabled (In particular peroxidase). The initial Lactococcus strain concentrations was 109 cfu/5ml of carrot juice, and were kept viable up to the end of fermentation (30 days).Tested Lactococcus lactis strain were capable of growing well on pure carrot juice without nutrient supplementation. Due to intense metabolism of the bacteria strain, carrot juice media were acidified to a pH level of less than 4.During fermentation, the amounts of sugars decreased significantly so that about 50% of which was taken after 24 hours. Degradation of carotenoids was less than 2%. In the case of phenolic compounds the reduction was minimal so that more than 80% of the total phenolic content of Carrot juices was retained in the final product.

Carrot juice with high nutritional value and helth benefits is one of the most consumed fruit juice in Iran. It is used as pasteurized without any contamination. But the important point in the industrial production of this product is to maintain the cloud stability. So, in this study, four types of hydrocolloids, namely guar, xanthan, pectin and carboxy methyl cellulose were used as stabilizer at the concentrations of 0.1, 0.3 and 0.5 (g/100mL). The cloud stability of pasteurized carrot juice was measured by a zetasizer device in the zeroth day and also by a spectrophotometer at 10-day intervals during the sixty-day storage at 5°C. Based on the results, the samples containing xanthan with the concentration of 0.3 and 0.5 were able to maintain the cloudy stability of carrot juice to the end of sixtieth day and showed a significant difference with the control and other treatments. On the other hand, the samples containing xanthan with the concentration of 0.3 obtained the acceptable score in the evaluation of sensory properties such as color, texture, flavor and taste.

The objective of this work was to investigate the effects of sonication on turbidity, viscosity, particle size distribution and total phenol of carrot juice. Carrot juice samples were sonicated according to a D-optimal design response surface with three factors of sonication temperature (25, 37.5 and 500C), sonication time (10, 20 and 30 min) and sonication power (350, 400w) at a constant frequency of 24 kHz. The results showed that ultrasound temperature (P<0.01) and time (P<0.01) significantly increased the turbidity of carrot juice samples. Also a significant change in particle size distribution was observed in sonicated juice due to cavitation effects. These resultes indicated that the cloud stability of sonicated carrot juice depends not only on pectin methylesteras inactivation but also on particle siz reduction. The highest particle size was observed in heat-treated juices due to heat coagulation of the colloidal materials. Sonication could not make significant alteration in the apparent viscosity of juice at different shear rates ranging between 0.1 and 100s-1, which indicated that the ultrasound or heat treatment juice followed the Newtonian flow behavior. However, the viscosity of heat-treated juice was significantly higher than untreated and sonicated samples. Ultrasound time significantly decreased the total phenolic contents of sonicated samples (P<0.01) but, significant difference was not observed between sonicated and heat-treated or untreated samples. These results suggest that, sonication with mild heat could used to obtain carrot juice with low Particle size and high turbidity, high viscosity and good retention of phenolic component.

In this study carrot juice samples were sonicated according to a D-optimal design response surface with different treatment of sonication temperature (25, 37.5 and 500C), sonication time (10, 20 and 30 min) and sonication power (350, 400w) at a constant frequency of 24 kHz. The results showed that ultrasound temperature (P<0.01), time (P<0.01) and interaction between time and temperature (P<0.01) significantly decreased the peroxidase enzyme activity of carrot juice samples and a prediction model obtained with high coefficients determination (R2 98%). Enzyme activity thermal treated juice processed at 90-880C for 4 min was undetectable. Ultrasound time significantly decreased the L-value, a-value, b-value, and TCD Blank (P< 0.05) of carrot juice samples. Whereas ultrasound temperature significantly increased the a value (P<0.01) and TCD Blank (P<0.05) samples. The obtained results showed that, ultrasound treatment significantly decreased peroxidase enzyme activity due to cavitational effects and reduced color parameters degradation specially a-value of carrot juice. Thus in order to maintain the quality of processed carrot juice; ultrasound processing could be accompanied by additional measures such as exclusion of oxygen, refrigerated storage and the use of natural enzyme inhibitors.

In this study, finding optimal processing conditions of carrot juice in relation to the effect of blanching on antioxidant compounds have been examined. Blanching was conducted through three immersion in water, citric acid 0.21 % solution and immersion in water and subsequently heating with microwave and were compared with the unblanch sample as the control sample. The tests applied are: extraction efficiency, measurement of ascorbic acid, anti radical activity (antioxidant characteristics), phenolic compounds contents and Carotenoids. The tests were conducted in four stages of pre-pasteurization, postpasteurization and after 15 days and 30 days of storage in the fridge. The experiments were done in completely random factorial form with three repetitions in each experiment. In order to compare the means, Duncan test at level of 0.05, was used. The statistical results indicated the blanching process and storage period have a significant effect on the antioxidant characteristics of carrot juice at the level of 0.05. Three methods used for comparing blanching anti-radical activity, phenolic compounds and ascorbic acid in the citric acid treatment of 0.21 % significantly was more than the other two methods. There is a strong correlation between the antiradical activity with β-carotene content, vitamin C and phenolic compounds (R2=0.9343).

The role of processing technology on carrot juice stability was studied in laboratory-scale pressing technique. To do so, the acidification and blanching conditions were changed. To assess the effect of acidification, different amounts of citric acid were added to the mash (i.e. 0.5 and 1 g citric acid/kg whole sample) and blanched at 60, 70, 80 °C for 10 min and compared untreated sample (without added acid). Acidifying with 0.5 g/kg showed significant effect on cloud stability. Although, the mash acidification improved the cloud stability, acidification following juice extraction even enhanced sedimentation rate. The mash blanching after acidification at 70 °C for 10 min concidreably inactivated of pectin esterase and intensified β - carotene extraction.