The pomegranate (Punica granatum L.) belongs to the family Punicaceae, which is planted around the world in various microclimatic areas. The pomegranate production has grown uninterruptedly, which is presumably due to the growing consumer awareness of the benefits attributed to pomegranate and its polyphenols. Pomegranate fruit has valuable compounds with functional and medicinal effects like antioxidant, anticancer, and anti-atherosclerotic effects. Storage of juice concentrate can have a dramatic impact on physicochemical quality. The bioactive compounds and antioxidant activity in fruit juice products are influenced by many external factors like different storage temperatures. Knowledge of the rheological behavior of juice products is essential for product development, design and evaluation of process equipment like pumps and piping. The pomegranate concentrate is so susceptible to the condition of storage, which results in a reduction in consumer acceptance and quality losses. Accordingly, the industrial concentrate stores are frozen (-20 ° C) which has a lot of costs to the producer. The purpose of this study was to evaluate the degradation visual color, the rheological characteristics of the granate juice concentrates, the phytochemicals stability, the antioxidant activity, and the reconstituted concentrate of the granate juice in the haze during storage at different temperatures for the best storage conditions To reduce the quality of losses and solve the problem of high cost of storage. Materials and methods : The concentrated pomegranate (Punica granatum (L.) cv. Rabab) juice used in this study is supplied from Narni (Green farm, Neyriz, Iran) factory. The pomegranate juice concentrate was poured into falcons for measuring physicochemical attributes and micro tubes for determination of antioxidant activity. Then the samples were divided into four parts and stored equally in four different temperatures (-20, 4, 20, and 35 ° C). The control samples were stored at -80 ° C as a fresh sample for storage period (140 days). The Folin-Ciocalteu reagent and 2,2-diphenyl-1-picyrylhydrazyl radical (DPPHº) were supplied from Sigma-Aldrich Company (St. Louis, MO, USA). All other chemicals were of analytical grade and purchased from Merck Company (Darmstadt, Germany). The total soluble solid (TSS) was determined with a digital refractometer (Carl Zeiss, Germany). Total insoluble solid was measured by centrifugation at (5000 × g) according to the IFFJP method 60 using a high speed centrifuge (Ibarz et al., 2011). The haze formation of reconstituted juice was determined by "settling" in a glass tube for 3 hours at room temperature. Color measurements of the juice samples were performed using a HunterLab (CHROMA METER CR-400/410, KONICA MINOLTA, Japan) after dilution. The rheological properties of the pomegranate juice concentrate stored in different temperatures were studied using a computer controlled rotational viscometer. Sample compartment was monitored at constant temperature (25 ° C) using a water bath / circulator, while TSS was 65 ° Brix. According to the methods described by Cárdenas et al., (1997), using a Brookfield cone and plate viscometer (DVII pro Brook field, USA) between shear rate of 0.5-200 (1 / s), the viscosity measurements were carried out. . Total phenol content of the samples was measured according to the Folin-Ciocalteu colorimetric method (Sun et al., 2007). Total flavonoid content in juices was determined by spectrophotometer according to the method of Chang et al. (2002). Radical scavenging activities of the samples were measured using DPPH as described by Mazidi et al., (2012). The ferrous ion reduction antioxidant power (FRAP) of the samples was measured calorimetrically according to the method by Fawole and Opara (2013). All analyzes were performed by the Statistical Analysis System (SAS) software V 9.1 (SAS Institute, Inc., Cary, NC, USA). Using the analysis of variance (ANOVA), the differences between means were determined for significance at P <0.05. Results and discussion: The industrial pomegranate juice concentrate is stored at (-20, 4, 20, and 35 ° C) for 20 weeks, and some physicochemical properties like the second turbidity, CIE Lab color parameters, the rheological properties, the bioactive component (total phenolic and flavonoid contents) and antioxidant properties (FRAP and DPPH) are investigated in order to determine the best condition of storage. The second turbidity was apparent among the samples stored at 35 ° C in the last four weeks. Although there were no significant differences among the L * values of the samples stored at -20, 4 and 20 ° C, a * and b * value of the samples stored at -20 and 4 ° C had the same reduction trend for 14 weeks . Even though the control samples had a shear thinning behavior, samples showed a dilatant behavior after storage. Antioxidant activities measured using DPPH and FRAP are sown with increasing time and temperature. Flavonoid content increased by increasing time and temperature. In conclusion, storage at 4 ° C for 14 weeks was the best storage condition for maintaining quality and reducing costs.
|Number of pages||10|
|Journal||Iranian Food Science and Technology Research Journal|
|Publication status||Published - 2018|
Farahmand, M., Golmakani, M-T., Farahnaky, A., & Mesbahi, G. (2018). Investigation of Psychochemical and Functional Properties of Pomegranate (Punica granatum (L.) cv. Rabab) Juice Concentrate During Storage Period at Different Temperatures. Iranian Food Science and Technology Research Journal, 13(5), 820-829. https://doi.org/10.22067/ifstrj.v1395i0.55415