Targeted and untargeted techniques coupled with chemometric tools for the evaluation of sturgeon (Acipenser gueldenstaedtii) freshness during storage at 4 °C

Polylactic acid amine-sensitive colorimetric indicator film loaded with eugenol/coumarin derivatives: Towards freshness indication and shelf-life extension of chilled pork

The action of microorganisms can lead to a decrease in food freshness and cause food safety issues. Traditional packaging can only provide a certain antimicrobial effect and cannot indicate the freshness of food, which can no longer meet the needs of consumers. The preparation of intelligent packaging films with antimicrobial effects and freshness indication is an effective solution. In this study, A novel electrospun intelligent food packaging film based on polylactic acid/eugenol/coumarin derivatives (7-(diethylaMino)-2-oxo-2H-chroMene-3-carbaldehyde) has been constructed to achieve the dual functions of antimicrobial and freshness indication for chilled pork. The antimicrobial layer loads eugenol coaxially into the fiber, which could scavenge 82.92 % of DPPH free radicals and effectively inhibit the growth of Escherichia coli and Staphylococcus aureus. The freshness-indicating layer showed fluorescence responsiveness to biogenic amines. The freshness-indicating and antimicrobial fibrous bilayer film turned green in practical application to indicate that the refrigerated pork had spoiled and was effective in extending the shelf life by 4-6 days. This study demonstrated the effectiveness of the bilayer film for preservation and freshness non-destructive testing of chilled pork. It provided a theoretical basis for the general application of film.

The Effect of Sodium Bicarbonate Injection on the Physico-Chemical Quality of Post-Harvest Trout

The muscle hardness of fish is an important parameter associated with meat quality, and the post-mortem decrease in the pH of fish tissue pH affects its physical properties. We hypothesized that maintaining a high pH in fish tissue after death would prevent protein denaturation and consequent textural deterioration. This study aimed to determine the effectiveness of sodium bicarbonate (SBC) injections in preventing tissue softening caused by low pH after death in trout. We injected varying molar concentrations of SBC in rainbow trout (Oncorhynchus mykiss; 0 M, 0.5 M, 0.75 M, and 1 M) after harvest, and the product quality was assessed at 0, 24, 48, 72, and 96 h of ice storage. Quality was evaluated using proximate analyses for color, pH, water holding capacity (WHC), texture profile, and rigor index. The 0 M group had the lowest pH, and the 0.75 M group had the highest pH at all time points during storage. We observed improved tissue texture during storage in fish treated with 0.75 and 1 M SBC. The texture profile analysis showed higher hardness, frangibility, and stickiness in the tail than in the other regions. These varying results can be explained by significant differences between parts of the fish and sampling point selection. We also observed the highest pH and WHC values in the groups injected with 0.75 and 1 M SBC during storage.

Effects of sous vide cooking combined with ultrasound pretreatment on physicochemical properties and microbial communities of Russian sturgeon meat (Acipenser gueldenstaedti)

BACKGROUND

The production of Russian sturgeon is expanding rapidly in China but it is necessary to adopt measures to extend the shelf life of sturgeon meat. Previous studies found that sous vide cooking (SVC) at 60 °C increased the protein and lipid oxidation. The addition of antioxidant substances reduced the acceptance of the product. The effect of combination SVC and ultrasound pretreatment was therefore investigated.

RESULTS

Results showed that SVC at 50 °C combined with ultrasound effectively restrained the growth of total viable counts (TVC) in samples. Meanwhile, the main dominant genera changed from Pseudomonas to Carnobacterium and the number of microbial species decreased. The odor profile of Russian sturgeon meat was more stable and the lipoxygenase (LOX) activity decreased more rapidly after treating with SVC and ultrasound. Importantly, more stable protein aggregates were formed in samples treated by SVC 50 °C together with ultrasound pretreatment, so the protein and lipid oxidation were slowed during storage. Higher springiness values were obtained and the color of sturgeon meat was lighter under these conditions.

CONCLUSION

The combination of SVC 50 °C and ultrasound pretreatment effectively inhibited the microbial growth of Russian sturgeon meat at lower oxidation levels. These findings theoretically support the preservation and development of sturgeon meat, and the application of SVC technology. © 2022 Society of Chemical Industry.

Effect of air fryer frying temperature on the quality attributes of sturgeon steak and comparison of its performance with traditional deep fat frying

In this study, the influence of air-frying temperature on the physical properties of sturgeon steaks was explored. Meanwhile, the comparison of traditional deep fat frying (TF) and air fryer frying (AFF) methods on the quality, flavor, and digestibility of sturgeon steaks were investigated. The results indicated that along with the increase of temperature (130, 160, and 190℃) for 15 min, the moisture content of AFF sturgeon steak surface decreased dramatically while that of interior was well preserved. The applied texture property analysis exhibited that AFF sturgeon steak showed the enhanced elasticity, low hardness, and soft texture. The results indicated that AFF sturgeon steak contained higher essential amino acid content than TF sturgeon steak. More flavor compounds (aldehydes, alcohols, and esters) were produced after AFF than TF. Although the digestibility of fried sturgeon steaks decreased after frying, AFF sturgeon steaks were digested rapidly in the stomach and intestine. Conclusively, AFF sturgeon steaks exhibited a crispy texture, appealing flavor, and low oil content. This work provides a certain reference for the suitable frying methods in the processing industry of sturgeon products.

A review combining emerging techniques with classical ones for the determination of biscuit quality: advantages and drawbacks

The production of biscuit and biscuit-like products has faced many challenges due to changes in consumer behavior and eating habits. Today's consumer is looking for safe products not only with fresh-like and pleasant taste, but also with long shelf life and health benefits. Therefore, the potentiality of the use of healthier fat and the incorporation of natural antioxidant in the formulation of biscuit has interested, recently, the attention of researchers. The determination of the biscuit quality could be performed by several techniques (e.g., physical, chemical, sensory, calorimetry and chromatography). These classical analyses are unfortunately destructive, expensive, polluting and above all very heavy, to implement when many samples must be prepared to be analyzed. Therefore, there is a need to find fast analytical techniques for the determination of the quality of cereal products like biscuits. Emerging techniques such as near infrared (NIR), mid infrared (MIR) and front face fluorescence spectroscopy (FFFS), coupled with chemometric tools have many potential advantages and are introduced, recently, as promising techniques for the assessment of the biscuit quality.

Differences in lipid composition of Bigeye tuna (Thunnus obesus) during storage at 0 °C and 4 °C

This study aimed to investigate the lipid oxidation and distribution in Bigeye tuna stored at 0 °C and 4 °C for 6 days. Tuna were evaluated by determining the peroxide value (POV), acid value (AV), anisidine value (AnV), polyene index, fluorescence ratio (FR), phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI) content, and major glycerophospholipid molecular species. The value of lipid oxidation indexes (POV, AV, AnV, FR, PC, PE and PI) increased as the storage time increased. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) results indicated that the major types of lipids included diacylglycerol (DAG), monoacylglycerol (MAG), phospholipid (PL), and triacylglycerol (TAG). At least 136 PC and 64 PE molecular species were identified in Bigeye tuna. The results of the confocal laser scanning microscope analysis indicated the distribution of TAG and PL particles. In addition, principal component analysis showed that the contents of PI and TAG were positively correlated with PC, polyene index and lipid content but negatively correlated with PI, POV, FR, AOV, AnV, MAG, and DAG, which might be explained by distinguishing the lipid parameters affecting lipid oxidation. Therefore, this study may provide a novel method to evaluate lipid changes and contribute to the balanced nutritional value of aquatic foods during cold storage.

A preliminary study on the potential of front face fluorescence spectroscopy for the discrimination of Moroccan virgin olive oils and the prediction of their quality

This study examines the feasibility of using front face fluorescence spectroscopy (FFFS) to authenticate 41 virgin olive oil (VOO) specimens collected from 5 regions in Morocco (Fez/Meknes, Eastern, Northern, Beni-Mellal/Khenifra, and Marrakech/Safi) during 2 consecutive crop seasons (2015-2016 and 2016-2017). By jointly applying factorial discriminant analysis (FDA) to the emission spectra acquired after excitation at 270, 290, and 430 nm, clear discrimination between VOOs according to their geographic origin (96.72% correct classification) and variety (95.12% correct classification) was observed. This trend was confirmed following the application of partial least squares regression (PLSR) to the fluorescence spectra, where excellent prediction of free acidity (R2 = 0.98) and peroxide (R2 = 0.96) values and good prediction of k232 (R2 = 0.88), k270 (R2 = 0.88), and chlorophyll content (R2 = 0.89) values were observed.