Applying bioactive ingredients in the formulation of foods instead of artificial preservatives is problematic because bioactive ingredients are unstable and sensitive to environmental conditions. The present study aimed to control the antioxidant activity of green tea extract (GT) through encapsulating in chitosan nanoparticles (CS-NP). The synthesized nanoparticles were analyzed by using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The encapsulation efficiency (EE), particle size, zeta potential, and polydispersity index (PDI) of GT-loaded CS-nanoparticles (CS-NP-GT) were assessed. Based on the results, the particle size and zeta potential related to the ratio of CS to GT of 1 : 0.5 were obtained as 135.43 ± 2.52 nm and 40.40 ± 0.2 mV, respectively. Furthermore, the results of FT-IR and XRD confirmed the validity of encapsulating GT in CS-NP. In addition, the antioxidant activity of GT increased after nanoencapsulation since the IC50 value of CS-NP-GT decreased to 6.13 ± 0.12 μg/ml. Finally, applying these particles for delivering GT polyphenols in foods is regarded as promising.

The probiotic yogurt, with additional essential oil researches, has increased recently. Bunium persicum Boiss is a critical medicinal wild growing plant in Iran dry areas. In this study, Lactobacillus acidophilus was exposed to stress with B. persicum essential oil (BEO), NaCl, bile salts, and their combinations by 50 minimum inhibitory concentration (MIC) and then inoculated to the yogurt samples, which were stored at 4°C for 28 days. Indepen-dent parameters in this article are BEO 500 and 1000 ppm that the physicochemical, sensory properties, and L. acidophilus of viability in yogurt samples were assessed within the time. A steady increase in syneresis percent-age and acidity was observed, while pH values were reduced in all samples. The L. acidophilus survival decreased during storage time in all treatments. In addition, sensory scores showed a reduction trend in the samples. The survival rate of probiotic bacteria is also impacted by redox potential. Increasing the oxidation and resuscitation potential and increasing the hydrogen peroxide concentration due to the bacteria metabolic activity are among the factors that reduce the probiotic bacteria population in yogurt during storage. The most viability of L. acidophilus under stress with BEO compared with other stress treatments may be due to slight changes in pH during this period than in the stress treatments. Generally, it can be argued that the usage of BEO, NaCl, and bile salts at a MIC of 50% in yogurt stored in the refrigerator for 21 days provided a suitable environment for the storage and transmission of L. acidophilus, as recommended to the consumer and, therefore, the current results confirmed that the addition of probiotic and these materials improved the physicochemical and sensory characteristics of yogurt.

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The annual production of aquatic animals is more than 120 million tons (FAO, 2020). This high amount of production has led to the construction of processing plants, eventually resulting in the production of non-consumable waste materials. The main wastes of aquaculture processing includes bones, waste, skin, and scales. If these wastes are used properly, on the one hand, they will produce valuable products and, on the other hand, they will prevent the possible environmental pollution (Ovissipour et al., 2009). In the recent years, the prevalence of bovine spongiform encephalopathy, population growth, increased aquatic fishing, and subsequently, the increase of waste has led experts to replace animal resources by aquatic hydrolyzed protein, introducing it to the public Bhaskar & Mahendrakar, 2008). Enzymatic hydrolysis is the most common method used to produce antioxidant peptides from aquatic resources. The hydrolysis process produces bioactive peptides with low molecular weight (2 to 20 amino acids), optimal performance, and beneficial biological properties. Bioactive peptides are inactive in the source protein sequence; they are released during proteolytic hydrolysis (Boutin et al., 2012;Sadeghian Amin et al., 2020).In general, microbial-derived enzymes are superior to other enzymes due to their good proteolytic properties and high heat and pH

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The present study aimed to investigate the impact of polylactic acid (PLA) integrated with nanochitosan (NC) composite film and Ziziphora Clinopodioides essential oil (ZCEO) on oxidative spoilage of rainbow trout fillets during a 9‐day refrigeration period. For this purpose, first, six degradable films including T1: PLA, T2: PLA + NC, T3: PLA + NC + 1% ZCEO, T4: PLA + NC + 1.5% ZCEO, T5: PLA + 1% ZCEO, and T6: PLA + 1.5% ZCEO were prepared. Next, the properties of the films were investigated. The results of the mechanical tests showed that ZCEO decreased the tensile strength and increased the elongation at the break of the PLA films. However, adding NC improved the mechanical characteristics of the PLA film. The outcomes of physical tests including moisture content (14.02%), solubility (17.41%), water vapor permeability (1.14 × 10−7 g s−1 m−1 Pa−1), and oxygen transmission rate (21.54 cm3.mm/m2.24 hr) showed that adding 1% ZCEO improved the film physical characteristics. Nevertheless, by adding 1.5% concentration EO to the PLA film, the values of water vapor permeability, porosity (according to the scanning electron microscopy), and turbidity increased and cross‐sectional pores were observed. Moreover, the films had high antioxidant properties (84.33%). In the next step, the effects of the mentioned films on the oxidative spoilage of rainbow trout fillets were investigated. The results of the chemical analysis in PLA film with the EO compared with the control treatment revealed the increasing trend of oxidation indices, in general. Moreover, increasing the concentration yielded better results such that all treatments containing EO showed satisfactory results up until the storage period ends. In most cases, adding NC affected the mentioned characteristics positively, and the best results were observed in T4 and then in T3. However, based on economics and the better mechanical and physical properties of T3, the film can be applied as an active packaging in fishery products.

This article is prepared to investigate the impacts of Cuminum cyminum essential oil (CEO), NaCl, bile salts, and their combinations on the viability of Lactobacillus casei in probiotic yogurt.The water distillation method was used to extract the CEO, and GC/MS was used to determine its constituents. Then, the CEO’s antibacterial activity, together with NaCl and bile salts, was investigated via the microdilution technique by determining the minimum inhibitory concentration (MIC) against L. casei. Further, the stress effects of 50% MIC on CEO, NaCl, and bile salts were examined by comparing the stress treatments with the control in terms of the L. casei population, pH, acidity, and syneresis percentage in probiotic yogurt during storage in the refrigerator for 28 days.According to the results, the L. casei population and pH decreased in all the treatments during the storage time, such that the intensity of the decrease in the control and CEO treatments was lesser than in other stress treat-ments (P<0.05). The acidity and percentage of syneresis during the storage time increased for all the treatments, with the increase being less in control and CEO than in the other stress treatments (P<0.05). The control and CEO treatments scored the highest in the sensory evaluation (P<0.05).Applying stresses below the MIC resulted in the survival of L. casei in the recommended amount (105–106 CFU mL–1) in the probiotic yogurt until the end of 28 days.