نشریه پژوهش های علوم و صنایع غذایی ایران
سال نوزدهم شماره 6 (پیاپی 84، Feb-Mar 2024)

Over the past decades, the use of natural additives has increased as an alternative to artificial ingredients in the food industry. The purpose of this study was to investigate the potential of pomegranate peel (PP) as a natural food additive. Many factors, including genotype, could affect the quality of PP as a by-product of juice production with many nutritional, functional and anti-infective properties. In this study, the most significant phytochemical characters of thirty Iranian pomegranate peels (IPP) from different genotypes, including total phenolic (TPC) and flavonoid content (TFC), and nine phenolic compounds were determined. The HPLC-DAD-MS results of PPEs revealed nine phenolic compounds in the IPP extracts. Punicalagin β, punicalagin α, and ellagic acid were the main components constituting 20.8–48.7, 13.9–30.1, and 1.6–13.4 μg/mg DW, respectively. The peel of IPP23 (Kabdar-Shirin-e- Behshahr) contained the highest quantity of polyphenolic compounds. Also, TPC and TFC of the peel extracts ranged between 66.38 and 181.41 mg GAE/ g DW and 38.5 to 144.13 mg RE/ g DW, respectively. Eventually, antioxidant potential estimated by the DPPH assay ranged between 4.1 and 14.4 μg/ml. The results showed that the antioxidant property of pomegranate peel extracts is significantly higher than the standard of gallic acid. Also, the peel of the genotypes that had high phenolic compounds were introduced as superior genotypes. The results of HCA showed that, among the studied genotypes, the peel of IPP23 can be introduced as a potential source of natural preservatives in the food industry.

The present investigation was done to study the effects of Lactococcus lactis (L. lactis) subsp. lactis on the shelf life of the vacuum-packaged Oncorhynchus mykiss. Fish fillets were prepared and divided into 5 different treatment groups including control (distilled water), 2% and 4% supernatant, and 106 CFU/g L. lactis subspecies lactis. The pH, Thiobarbituric Acid Reactive Substances (TBARS), Total volatile Nitrogen (TVN), and Peroxide Value (PV) of the fillets were determined on days 0, 5, 10, and 15 while maintained at 4˚C. Protein expression and destruction were analyzed using the SDS-PAGE. The organoleptic assessment was done using five expert sensory panelists. Contents of TBARS, TVN, pH, and PV were increased throughout the storage period (P <0.05). An increase in the concentration of supernatant caused a significant decrease in the content of TBARS, TVN, pH, and PV (P <0.05). The highest and lowest contents of TBARS, TVN, pH and PV on 15th day were belonged to the control (3.367±0.04 mg MDA/kg) and pure bacteria (0.70±0.02 mg MDA/kg), control (87.20±6.40 mg/100g) and 4% supernatant (40.79±0.61 mg/100g), pure bacteria (6.23±0.04) and 4% supernatant (5.44±0.07) and control (12.22±0.01 meq/kg) and 4% supernatant (3.08±0.06 meq/kg) groups, respectively. Protein destruction was lower in the fillet samples treated with pure bacteria and 4% supernatant. The highest scores of the odor, flavor, texture, and color were obtained for fillets treated with 4% supernatant, pure bacteria, pure bacteria, and 4% supernatant and pure bacteria, respectively. The results revealed that treating O. mykiss fillets with 4% supernatant and 106 CFU/g of pure L. lactis subsp. lactis can extend the shelf life of O. mykiss fillets.

Due to its health benefits, fresh sprouted cereals are considered popular food source. They are very sensitive and highly susceptible to microbial spoilage during transportation, processing, and storage. This phenomenon makes them potentially high-risk fresh products. This study aimed to assess the effect of emulsion coating consisting of Dracocephalum kotschyi essential oil (0, 50, 150, 250, 300 ppm)-chitosan solution (0, 0.3, 0.38, 0.63, 0.75%) during the immersion time (10, 25, 55, 85, 100 s) on the microbial properties of fresh sprouted wheat stored at 4°C. The Response Surface Methodology (RSM) was adopted in modeling the independent variables’ effects. The results shown that increase in the essential oil and chitosan solution concentration reduced the microbial spoilage. High concentration of Dracocephalum kotschyi oil decreased the fungus population after 12 days. Coating of sprouted wheat at optimized level of independent variables (0.62% chitosan, 57 ppm Dracocephalum kotschyi oil and 29.49 s immersion time) reduced the microbial and fungal populations. This treatment can reduce weight loss, and maintain tissue firmness, total phenolic, and ascorbic acid content of the sprouted wheat during cold storage, with no effect on its sensory properties. Our findings indicate that nanoemulsion coating based on chitosan and Dracocephalum kotschyi oil at appropriate levels could be beneficial in maintaining sprouted wheat quality and increasing its shelf-life.

The increasing growth of cardiovascular diseases, high blood pressure, and hardening of the vessel walls as well as obesity in many countries has made low-fat and low sodium pizza cheese one of the subjects of study all over the world. The effects of four important independent variables including inulin (0-0.025 %), pre-gelatinized starch (0-0.5 %), NaCl (0.35-1%), and KCl (0.35-1%) were studied. The fat content of imitation pizza cheese was significantly decreased to 11.91% with the increased levels of inulin and starch substitution (p<0.05). Also, its moisture and pH values were significantly different (p < 0.05). The increased levels of pre-gelatinized starch and inulin reduced hardness (from 5.04 to 3.55) and adhesiveness (from 4368.89% to 1640.54%), however, increased cohesiveness (from 0.365 to 0.43) and springiness (from 0.456 to 0.545). NaCl and KCl increased the hardness of the product. Inulin and starch led to decrease the a* value. The b* value decreases with the increase of inulin and increases with the increase of modified starch. The formulation containing 0.19% inulin, 0.4% pre-gelatinized starch, 0.35% NaCl, and 0.50% KCl was found as the optimal formulation for low-fat imitation cheese. Results of scanning electron microscope (SEM) images revealed that inulin crystals were accumulated in the continuous phase, which this can lead to important changes in the sensory and textural properties. The study concludes that inulin or starch can be used to replace up to 3.6% of fat in the imitation pizza cheese and 0.35% NaCl-0.50% KCl to lower the sodium content of the product.

In recent years, the use of propolis in food products has received attention owing to its functional role. This study was conducted to investigate the effect of different concentrations of propolis extract on the total polyphenol content and antioxidant activity of raw milk. For this purpose, an aqueous extract of dry propolis was prepared and stored in dark-colored bottles at 4 °C until the day of experiments. The propolis extract was added to raw milk in concentrations of 0, 4.7, 9.1, 16.6, and 28.5%. Total phenolic content and antioxidant activity were measured using the colorimetric Folin-Ciocalteu method and DPPH assay, respectively. Measurements were performed on the first day at zero hour and after 6 and 24 h of treatment, and the storage temperature was maintained at 5°C until analyzed. The amount of total polyphenol increased with the increase in the concentration of propolis extract in the treated milk in 0 hour; accordingly, the lowest and the highest amounts of total polyphenol were related to control milk and milk containing 28.5% propolis extract, respectively. A decreasing trend was observed in total polyphenol in the control sample and raw milk containing 4.7% propolis extract during 24 hours. There was an increase in total polyphenol content in raw milk containing 9.1% and 16.6% propolis extracts, the trend of changes in raw milk containing 28.5% extract was insignificant. The addition of propolis extract caused an increase in the antioxidant activity and total phenolic content in raw milk. According to the results, it is recommended to carry out more studies to clarify the functions of propolis's total polyphenol content and its interaction with milk proteins.

Preparing air-in-oil-in-water (A/O/W) double emulsion involves two key steps: oleofoam formation and dispersion of the oleofoam in an aqueous solution containing protein as an emulsifier and hydrocolloid as a thickening agent. This study aimed to investigate the effect of oleofoam level and varying concentrations of protein-polysaccharide ratios on the thermal stability, encapsulation yield and rheological properties of A/O/W double emulsion. An oleofoam was obtained using a lipophilic emulsifier (distilled monoglyceride MG) and sunflower oil at 5°C with maximum stability. Two levels of oleofoam (20% and 25 wt %) were added to an aqueous solution containing different concentrations of sodium caseinate (SC) (5, 8, and 10 wt %) and kappa carrageenan (KC) (0.4 and 0.8 wt %). Results indicate that oleofoam level did not significantly affect air encapsulation efficiency and particle size, while protein-polysaccharide ratios could significantly impact all properties of A/O/W double emulsion. Increasing the concentration of sodium caseinate and kappa carrageenan improved thermal stability and encapsulation yield while simultaneously reducing particle size. All A/O/W emulsions exhibited shear thinning behavior among the range of shear rates studied, indicating significant potential for food applications.