Inhibition of quality loss in chilled megrim (Lepidorhombus whiffiagonis) by employing citric and lactic acid icing

This study focuses on the quality retention of megrim (Lepidorhombus whiffiagonis) during chilled storage. Aqueous solutions of two different concentrations of citric (CA) and lactic (LA) acids were employed as icing media (0.125% CA–0.050% LA and 0.175% CA–0.050% LA, respectively; w/v). The effects of each solution on microbial activity, lipid damage and sensory acceptance were monitored for up to 13 days of storage. Lower (P < 0.05) bacterial growth was detected according to microbiological (aerobe and psychrotroph counts) and chemical (trimethylamine‐N and pH) assessments, which led to an enhancement of sensory appreciation. Whereas control fish were determined as unacceptable at day 13, the acid‐iced fish were still acceptable at that time. Concerning lipid damage, an inhibitory effect (P < 0.05) on fluorescent compound formation was observed in the acid‐iced fish. Present results allow to conclude that the use of a CA–LA icing system can provide a profitable strategy to obtain higher quality chilled fish.     

Effect of previous frozen storage on quality changes of grass carp (Ctenopharyngodon idellus) fillets during short‐term chilled storage

The effect of chilled, frozen and freeze‐chilled storage on quality of grass carp fillets and soups was evaluated by sensory score, total aerobic counts and biochemical quality. Fish fillets were stored at 4 °C for 6 days (T1), ?40 °C for 12 h and then at ?20 °C for 5 days (T2), ?40 °C for 12 h and then at ?20 °C for 5 days, followed by at 4 °C for 4 days (T3). T1 showed higher sensory score, salt‐soluble protein content, better colour and texture qualities than T2 and T3 within 3 days. All fillets kept good quality based on the acceptable limit of sensory score, total volatile basic nitrogen and total aerobic count during storage time. According to the transportation and retail time, chilled storage is appropriate when it is within 3 days. If it extends for 5 days, freeze‐chilling treatment keeps better quality, but later chilled fillets should be retailed within 4 days.     

Effect of high‐pressure treatments on microbial loads and physicochemical characteristics during refrigerated storage of raw milk Serra da Estrela cheese samples

This work studied the effect of high pressure processing (HPP) at 400, 500 and 600 MPa during 10, 5 and 3 min, respectively, on samples ewe cheese manufactured from raw milk, during storage (100 days) at 5 °C. Total aerobic mesophilic and lactic acid bacteria were slightly affected, decreasing by about 1.0 and 0.82 log CFU g^?1, respectively, immediately after HPP treatment at 600 MPa for 3 min, while Enterobacteriaceae, yeasts and moulds, and Listeria innocua were reduced to below the quantification limits. Lactic acid bacteria decreased further during storage, showing increasing inactivation as the pressure level increased. Physicochemical parameters (water activity, moisture content, pH and titratable acidity) were generally not affected by HPP, while lipid oxidation increased throughout storage, with HPP samples showing lower values (50–66%) at 100 days of storage. The results indicated that HPP has potential to improve cheese microbial safety and shelf‐life, with a lower lipid oxidation level than nonpressurised cheese.     

Viability of Lactobacillus acidophilus in rice bran‐enriched stirred yoghurt and the physicochemical and sensory characteristics of product during refrigerated storage

This study was aimed at investigating the fortification of probiotic yoghurt with rice bran to increase nutritional properties of the product. The different levels of rice bran (0.3%, 0.6%, 0.9% and 1.2%) were incorporated into milk. The yoghurt samples were produced after pasteurisation, addition of starter culture and 1% Lactobacillus acidophilus suspension (6 × 10⁸ CFU mL^?1) and incubation. During sample storage in refrigerator, the viability of L. acidophilus, viscosity and physicochemical and sensory properties of product were investigated. Rice bran significantly increased the viability of L. acidophilus (P < 0.05). In addition, all probiotic yoghurts incorporating rice bran indicated higher viscosity and acidity and lower pH and syneresis compared to plain yoghurts. Furthermore, increments in rice bran incorporation levels resulted in a reduction in consumers' sample preferences. In general, the addition of rice bran at a suitable level could increase L. acidophilus viability and improve quality attributes of yoghurt.     

Effects of UV‐C irradiation on the physiological and antioxidant responses of button mushrooms (Agaricus bisporus) during storage

Novel postharvest technology not only preserves the freshness of fruits and vegetables, but also triggers the biosynthesis of antioxidant compounds as a secondary response. This study examined the browning and antioxidant properties of button mushrooms (Agaricus bisporus) treated with UV‐C irradiation in combination with cold storage. Three sample preparation methods for antioxidant activity analysis, simulative gastrointestinal digestion (GAR), direct evaluation (QUENCHER) and traditional solvent extraction (TSE), were used to evaluate the samples, and followed analysing by both FRAP and ABTS assays. Broadly, the results indicated that, following an initial increase, UV‐C irradiation suppressed browning during a cold storage period of 18 days. And the total phenolic content of the treated mushrooms were higher than that of the control, while the ascorbic acid content decreased sharply during storage, and UV‐C treatment had negative effects on ascorbic acid content. Results from the QUENCHER and GAR methods showed that UV‐C treatment significantly increases the total antioxidant capacity (TAC) of mushrooms throughout the entire storage period, and have a larger magnitude than that of TSE method. In conclusion, the combination of UV‐C irradiation and cold storage showed great potential for improving mushroom quality as a new postharvest technology.     

Effects of Mentha longifolia L. essential oil and Lactobacillus casei on the organoleptic properties and on the growth of Staphylococcus aureus and Listeria monocytogenes during manufacturing,ripening and storage of Iranian white‐brined cheese

This research evaluated the effects of Mentha longifolia L. essential oil (EO) in concentrations 0, 50, 150 and 300 ppm and Lactobacillus casei (10⁸–10⁹ CFU/mL) on the growth of Staphylococcus aureus and Listeria monocytogenes during the manufacturing, ripening and storage of Iranian white‐brined cheese. The growth of the two pathogens was significantly reduced (P < 0.01) by both EO concentrations ≥50 ppm and probiotic and their combination in the standard manufacturing and storage process conditions of the cheese. Furthermore, the treatment containing 150 ppm of this EO combined with probiotic had a favourable inhibitory effect on the growth of two pathogenic micro‐organisms and also was the most appropriate treatment in sensory assessment. The synergistic effects of the above‐mentioned concentration level between the essential oil and probiotic were significant compared to other treatments, including essential oil and probiotic only. Thus, a lower concentration of this EO can be used when it is combined with this probiotic.     

Mineral composition,antioxidant and cytotoxic biopotentials of wild‐growing Ganoderma species (Serbia): G. lucidum (Curtis) P. Karst vs. G. applanatum (Pers.) Pat.

The aim of this work was to analyse mineral composition and chemical profile of two nonedible fungal species: Ganoderma lucidum and Ganoderma applanatum (Fru?ka Gora, Serbia) vs. their antioxidant (ABTS and A.E.A.C. assay) and cytotoxic biopotentials (MTT assay on MCF‐7). Both species were analysed for their content of macro‐ and microelements by atomic absorption spectrophotometry, while phenolic profile of EtOH and H₂O extracts was examined by LC‐MS/MS technique. Both species mostly contained the following ions: K⁺ > Ca²⁺ > Mg²⁺ > Mn²⁺ > Zn²⁺ > Cu²⁺ > Cr³⁺. Among nine phenolic compounds, the highest content of vanillic acid was detected in G. applanatum extracts while protocatechuic acid in EtOH extract and quinic acid in H₂O extract were mostly contained in G. lucidum. Ganoderma applanatum EtOH extract showed the best antioxidant activities related to its phenolic and flavonoid content. Further, the best cytotoxic effect after 72 h was observed in this extract as well.     

Antioxidant activity in HepG2 cells,immunomodulatory effects in RAW 264.7 cells and absorption characteristics in Caco‐2 cells of the peptide fraction isolated from Dendrobium aphyllum

DA‐P, fraction of peptides with a molecular weight <1 kDa isolated from Dendrobium aphyllum, was analysed in three types of cell lines to verify its bioactivity and absorptivity. The cellular antioxidant activity of DA‐P in HepG2 cells was used and results revealed an EC50 of 2.88 ± 0.143 mg mL^?1 and a CAA unit of 63.46 ± 2.11 μm QE/100 g peptides. DA‐P treatment enhanced the secretion of cytokines in RAW 264.7 cells. After demonstrating the presence of tight junctions in Caco‐2 monolayers, the absorption was 25.57% ± 0.016% and 19.7% ± 0.012% from different sides. The relatively high absorption indicated that the antioxidant‐relevant immune functions of DA‐P had a greater possibility to be absorbed by Caco‐2 cells. Free amino acids and LC‐MS/MS analysis indicated the degradation and expulsion of components after the absorption of DA‐P, and Ser‐Ser‐Arg was able to come across the monolayers.