Effects of CO2 on the physicochemical, microbial, and sensory properties of pork patties packaged under optimized O2 levels

The storage quality characteristics of fresh pork patties were investigated under 80% O2 modified atmosphere packaging (MAP80:20 = 80% O2/20% CO2) and 40% O2 MAP with various CO2 levels (MAP40:20 = 40% O2/20% CO2/40% N2; MAP40:40 = 40% O2/40% CO2/20% N2; MAP40:60 = 40% O2/60% CO2). Packaged patties were stored for 16 days at 4 °C to monitor their physicochemical (pH, instrumental color, oxidative stability, and fatty acid profile), microbial, and sensorial changes. Results suggested that decreasing O2 levels from 80% to 40% significantly inhibited the lipid oxidation of patties but led to a lower (P < 0.05) color stability. Elevating CO2 levels from 20% to 60% in combination with 40% O2 significantly suppressed bacterial growth and total volatile basic nitrogen production, and thus rendered patties with a better sensory quality and a similar meat color to 80% O2. However, increased CO2 levels promoted lipid oxidation through reducing the antioxidant capacity of patties, which was attributed to a CO2-induced reduction in superoxide dismutase and glutathione peroxidase activities during storage rather than a pH reduction or changes in fatty acid composition. Overall, 40% O2/40% CO2/20% N2 is a realistic alternative for pork patties to improve meat quality and extend the shelf-life to over 16 days.

Changes in the thermal stability and structure of myofibrillar protein from quick-frozen pork patties with different fat addition under freeze-thaw cycles

Changes in thermal stability and structure of myofibrillar protein from pork patties with different fat addition (0%, 5%, 10%, 15% and 20%) under freeze-thaw (F-T) cycles were discussed. The results showed that the total sulfhydryl, reactive sulfhydryl, free amino group, α-helix and β-sheet contents, fluorescence intensity (FI), and protein thermal stability (T_max, ∆H_total) of samples with the same fat content were significantly decreased, while the β-turn and random-coil content and the maximum fluorescence emission wavelength (λ_max) were significantly increased with increasing F-T cycles (P < 0.05). These changes in samples with 20% fat at the 5th F-T cycle were obvious and were verified by the decreases in ∆H_total (26.1%), reactive sulfhydryl (16.1%), and FI (16.8%) compared with the patties without fat. Therefore, repeated F-T cycles could decline the thermal stability of protein, destroy the protein structure of patty, and the changes were positively correlated with fat content of patty.

Antioxidant and antimicrobial activity of Agave angustifolia extract on overall quality and shelf life of pork patties stored under refrigeration

Agave plants contain different bioactive compounds that are related to different biological activities; however, the application of Agave as a food additive has rarely been evaluated. The objective of this study was to evaluate the antioxidant and antimicrobial potential of Agave angustifolia extract (AAE) on pork patties stored at 4 °C during 10 days. According to the spectrophotometric analysis, AAE contained phenolic compounds and saponins. In addition, AAE exhibited antioxidant activity based on DPPH, ABTS and FRAP assays (94.2, 239.1 and 148.8 µmol ET/g, respectively). Likewise, AAE showed bactericidal activity against Staphylococcus epidermidis (60 mg/mL) and Escherichia coli (60 mg/mL). AAE demonstrated a protective effect against oxidative processes (TBARS and metmyoglobin) in patties compared to the control group. Mesophilic and psychotropic counts showed that AAE exhibited a weak antimicrobial effect. AAE showed a protective effect on redness and lightness (at 3 and 10 days of storage, respectively). Sensory evaluation found that AAE had no effect on the analyzed parameters. AAE exhibited antioxidant activity that preserve quality and extended the shelf life of pork patties.

Oak wood extracts as natural antioxidants to increase shelf life of raw pork patties in modified atmosphere packaging

The use of antioxidants and refrigeration storage in modified atmosphere packaging, MAP, are the main strategies to slow down the oxidative and microbial deterioration of fresh meat. Synthetic antioxidants are commonly used for this purpose, however due to their controversial health effects, natural alternatives for their replacement are being looked for. The main aim of this work is the evaluation of pressurised aqueous extracts from oak wood as natural preservative of pork patties. The effect of different amounts of oak wood extracts (0.05, 0.5 and 1.0%) on the self-life of pork patties packed in MAP in refrigeration during 12 days were studied in comparison with the use of sodium ascorbate as synthetic preservative. Samples treated with oak wood extracts showed lower lipid oxidation, higher antioxidant capacity and an inhibitory effect on the enterobacteria growth. Furthermore, the addition of oak wood extracts resulted in a dramatically decrease of the volatile compounds coming from the lipid oxidation reactions. On the other hand, it is noteworthy that the use of oak wood extracts modified sensorial characteristics. Intensity colour was higher and new sensorial features such as oak wood and sweet spices appeared which were well appreciated.

Physicochemical and textural properties of pork patties as affected by buckwheat and fermented buckwheat

This study was investigated to assess the effects of buckwheat (BW) and fermented buckwheat (FBW) on the proximate compositions, pH change, cooking quality, lipid oxidation, textural properties, and sensory characteristics of pork patties. Pork patties treated with BW and FBW were divided into six groups; Con, non-treated patties; T0, reduced fat patties; T1 and T2, addition of 1 and 3 % BW; FT1 and FT2, addition of 1 and 3 % FBW. FBW showed significantly higher antioxidant activity and total phenolic contents than BW (P < 0.05). FT2 had significantly lower level of lipid oxidation than other groups (P < 0.05). The addition of BW and FBW increased the crude fiber content in pork patties, whereas it decreased the crude fat content compared to the control group (P < 0.05). BW and FBW significantly reduced expressible drip and cooking loss (P < 0.05). Pork patties prepared with BW and FBW exhibited higher redness value of uncooked and cooked patties. Texture profile analysis of patties revealed that the addition of BW and FBW significantly decreased the hardness and increased tenderness. The results suggested that BW and FBW exhibited substantial effects on improving the quality of pork patties. The 1 % BW (T1) and FBW (FT1) appeared to be the most effective means of improving the overall properties of pork patties.