Effect of rose polyphenols on oxidation, biogenic amines and microbial diversity in naturally dry fermented sausages

Antioxidant and Antimicrobial Effects of Catechin Liposomes on Chinese Dried Pork

In this study, catechin (CT), catechin liposome (CTL), and α-tocopherol (TP) were added to Chinese dried pork to achieve a healthy lipid composition. Their effectiveness in prevention of lipid oxidation was determined by measuring the values of thiobarbituric acid-reactive substances and peroxides. The total viable count in samples was used to identify the antimicrobial activities of CT, CTL, and TP, and the pH values of the samples were determined. Chinese dried pork with antioxidants added at 600 mg/kg was subjected to sensory evaluation. Thiobarbituric acid-reactive substance values, peroxide values, and total viable counts indicated that CTL significantly enhanced the antioxidant and antibacterial effects of CT on Chinese dried pork, especially after storage at room temperature for 25 days. Compared with the two other antioxidants, CTL could better maintain the pH stability of Chinese dried pork at room temperature. Sensory evaluation revealed that the scores of CTL were better than those of CT and TP in terms of preserving the color, flavor, tenderness, and overall acceptability of Chinese dried pork. Use of CTL in Chinese dried pork had good antioxidant and antibacterial effects and maintained color, flavor, and tenderness at a relatively stable level, suggesting that CTL could be used as an antioxidant in Chinese dried pork to enhance oxidative stability and prolong shelf life.

L. inermis-loaded nanofibrous scaffolds for wound dressing applications

Since ancient times, some herbal medicines have been extensively used for burn and wound treatments, showing preference to the common synthetic medications by virtue of having less side effects and faster healing rate. In this study, hybrid nanofibrous scaffolds of poly-l-lactic-acid (PLLA) and gelatin incorporated L. inermis were fabricated via electrospinning technique. Morphology and characteristics of the scaffolds were studied by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR), respectively. The release profile of the L. inermis from the nanofibers was also assessed in vitro. Moreover, the structural stability of the released L. inermis from the nanofibers was evaluated using high-performance liquid chromatography (HPLC). The nanofibers showed a gradual release of L. inermis up to two days while the intact structure was preserved. Furthermore, antibacterial assay demonstrated that L. inermis-loaded nanofibrous scaffolds could effectively kill E. coli and S. aureus within 2 h. Finally, biocompatibility of the nanofibers was proven on 3T3 fibroblasts. Therefore, the L. inermis loaded PLLA-Gelatin nanofibers showed a potential application as a wound dressing in order to control wound infections.

Hyperspectral Imaging in Tandem with R Statistics and Image Processing for Detection and Visualization of pH in Japanese Big Sausages Under Different Storage Conditions

The potential of hyperspectral imaging with wavelengths of 380 to 1000 nm was used to determine the pH of cooked sausages after different storage conditions (4 °C for 1 d, 35 °C for 1, 3, and 5 d). The mean spectra of the sausages were extracted from the hyperspectral images and partial least squares regression (PLSR) model was developed to relate spectral profiles with the pH of the cooked sausages. Eleven important wavelengths were selected based on the regression coefficient values. The PLSR model established using the optimal wavelengths showed good precision being the prediction coefficient of determination (R_p² ) 0.909 and the root mean square error of prediction 0.035. The prediction map for illustrating pH indices in sausages was for the first time developed by R statistics. The overall results suggested that hyperspectral imaging combined with PLSR and R statistics are capable to quantify and visualize the sausages pH evolution under different storage conditions.

PRACTICAL APPLICATION

In this paper, hyperspectral imaging is for the first time used to detect pH in cooked sausages using R statistics, which provides another useful information for the researchers who do not have the access to Matlab. Eleven optimal wavelengths were successfully selected, which were used for simplifying the PLSR model established based on the full wavelengths. This simplified model achieved a high R_p² (0.909) and a low root mean square error of prediction (0.035), which can be useful for the design of multispectral imaging systems.

The Effects of Using Sodium Alginate Hydrosols Treated with Direct Electric Current as Coatings for Sausages

We investigated the effect of sodium alginate hydrosols (1%) with 0.2% of NaCl treated with direct electric current (DC) used as a coating on microbial (Total Viable Counts, Psychrotrophic bacteria, yeast and molds, Lactic acid bacteria, Enterobacteriaceae), physiochemical (pH, lipid oxidation, antioxidant activity, weight loss, color) and sensory properties of skinned pork sausages or with artificial casing stored at 4 °C for 28 days. Moreover, the cytotoxicity analysis of sodium alginate hydrogels was performed. The results have shown that application of experimental coatings on the sausage surface resulted in reducing all tested groups of microorganisms compared to control after a 4-week storage. The cytotoxicity analysis revealed that proliferation of RAW 264.7 and L929 is not inhibited by the samples treated with 200 mA. Ferric reducing antioxidant power (FRAP) and free radical scavenging activity (DPPH) analyses showed that there are no significant differences in antioxidant properties between control samples and those covered with sodium alginate. After 28 days of storage, the highest value of thiobarbituric acid-reactive substances (TBARS) was noticed for variants treated with 400 mA (1.07 mg malondialdehyde/kg), while it was only slightly lower for the control sample (0.95 mg MDA/kg). The obtained results suggest that sodium alginate treated with DC may be used as a coating for food preservation because of its antimicrobial activity and lack of undesirable impact on the quality factors of sausages.