Postmortem changes in the freshness and volatile compounds of grass carp (Ctenopharyngodon idella)

Inhibitory effects of glutathione peroxidase on microbial spoilage of crayfish (Procambarus clarkii) during refrigerated storage

The variety of enzyme-based biological preservatives is limited. This study evaluated the effects of glutathione peroxidase (GSH-Px) on the quality of crayfish during refrigerated storage by measuring the pH, total volatile basic nitrogen, trimethylamine, and microbial contamination in crayfish muscle simulation system. The results revealed that 0.3% GSH-Px (CK3) not only suppressed the degradation of nitrogenous substances but also decreased the contamination levels of total viable, Enterobacteriaceae, and Pseudomonas counts (P < 0.05). Furthermore, the populations of Lactococcus, Aeromonas, and Massilia differed in the CK3 group compared to the other groups (P < 0.05) at the end of the storage (day 15). Moreover, the principal coordinate analysis showed that the colony composition of CK3 stored for 15 days was similar to that of the control group stored for 10 days. Therefore, GSH-Px exhibits antibacterial activity against Gram-negative bacteria and has good application potential in freshwater aquatic product preservation.

The role of ultraviolet radiation in the flavor formation during drying processing of Pacific saury (Cololabis saira)

BACKGROUND

Traditional sun-drying aquatic products are popular and recognized by customers, owing to their unique flavor and long-term preservation. However, the product quality and production efficiency cannot be guaranteed. Cololabis saira is rich in unsaturated fatty acids, which are susceptible to hyperoxidation during the drying process. This study aimed to make clear the role of ultraviolet (UV) radiation in flavor formation during drying processes of Cololabis saira to develop a modern drying technology.

RESULTS

Lipid oxidation analysis revealed that moderate hydrolytic oxidation occurred in the UV-assisted cold-air drying group due to the combined influence of UV and cold-air circulation, resulting in the thiobarbituric acid reactive substances value being higher than that of cold-air drying group but lower than the natural drying group. Hexanal, heptanal, cis-4-heptenal, octanal, nonanal, (trans,trans)-2,4-heptadienal, (trans,trans)-2,6-nonanedial, 1-octen-3-ol, heptanol, 2,3-pentanedione, 3,5-octadien-2-one and trimethylamine were identified as the characteristic flavor odor-active compounds present in all Cololabis saira samples. Yet, during the natural drying process, sunlight promoted the lipid oxidation, resulting in the highest degree of lipid oxidation among three drying methods. Light and heat promoted lipid oxidation in Cololabis saira prepared through natural drying process, leading to a large accumulation of volatile compounds, such as 3-methylbutyraldehyde, 2,3-pentanedione, 1-propanol, and 3-pentanone. Cold air circulation inhibited lipid oxidation to some extent, resulting in a blander flavor profile. More cis-4-heptenal, cis-2-heptenal, octanal and 2-ethylfuran accumulated during the UV-assisted cold-air drying process, enriching its greasy flavor and burnt flavor.

CONCLUSION

UV-assisted cold-air drying could promote moderate lipid oxidation, which is beneficial for improving product flavor. To sum up, UV radiation played a crucial role in the flavor formation during the drying process of Cololabis saira. © 2024 Society of Chemical Industry.

Variations in volatile flavour compounds in Crataegi fructus roasting revealed by E-nose and HS-GC-MS

Introduction

Crataegi fructus (CF) is an edible and medicinal functional food used worldwide that enhances digestion if consumed in the roasted form. The odour of CF, as a measure of processing degree during roasting, significantly changes. However, the changes remain unclear, but are worth exploring.

Methods

Herein, the variations in volatile flavour compounds due to CF roasting were investigated using an electronic nose (E-nose) and headspace gas chromatography-mass spectrometry (HS-GC-MS).

Results

A total of 54 components were identified by GC-MS. Aldehydes, ketones, esters, and furans showed the most significant changes. The Maillard reaction, Strecker degradation, and fatty acid oxidation and degradation are the main reactions that occur during roasting. The results of grey relational analysis (GRA) showed that 25 volatile compounds were closely related to odour (r > 0.9). Finally, 9 volatile components [relative odour activity value, (ROAV) ≥ 1] were confirmed as key substances causing odour changes.

Discussion

This study not only achieves the objectification of odour evaluation during food processing, but also verifies the applicability and similarity of the E-nose and HS-GC-MS.

A colorimetric gas-sensitive array sensor using filter paper for the analysis of fish freshness

We developed a colorimetric array sensor using filter paper (FPCAS) to detect fish freshness. After 16 common indicators sensitive to trimethylamine, aldehydes, and sulfides were screened, they were further sensitized and dotted on filter paper to prepare FPCAS. The results revealed that FPCAS was beneficial in the later detection of fish storage. When we used FPCAS to detect the freshness of bass stored at 30 °C, total discriminant accuracy was 100%, and cross-validation accuracy was 63.5%. When detecting the freshness of bass stored at 4 °C, the total discriminant accuracy reached 100%, and cross validation accuracy was 93.3%. Therefore, FPCAS can distinguish fish freshness under commercial cold storage conditions. In addition, the indicators and filter paper used for FPCAS are low-cost. Consequently, FPCAS is a good freshness indicator of meat and fish.

Quality and volatile compound analysis of shrimp heads during different temperature storage

This study aimed to investigate volatile compounds and quality traits of shrimp heads stored at 20 °C, 4 °C, -3 °C, and -18 °C. With increased storage time, sensory scores gradually decreased, while pH and TVB-N content showed a gradually increase trend. L* showed a decreasing and then increasing tendency. The radar chart and principal component analysis showed variation changes. Three compounds including 2-decanone, dimethyl disulphide and dimethyl tetrasulphide, four compounds including 2-pentanone, 3-methyl-1-butanol, 2-methylbutyric acid, and 2,3,5-trimethylpyrazine, and 3-methylbutyraldehyde were the characteristic volatiles for the samples stored at 20 °C, 4 °C, and -3 °C, respectively. Twenty-five volatile compounds were key volatile compounds, among which nine were potential classification compounds with high variable importance in projection values. Trimethylamine and 2-nonanol were selected as potential markers of spoilage. The study provides the theoretical basis for quality and volatile compound investigations for shrimp heads with further high-quality utilization.

Comparison of different edible parts of bighead carp (Aristichthys nobilis) flavor

The study aims to obtain the information on taste and odor among different edible parts (white dorsal meat, white abdomen meat, white tail meat, and dark meat) of bighead carp. The results showed that the white dorsal meat and white abdomen meat had the higher content of total amino acids among all edible parts of bighead carp samples. The highest inosine monophosphate and adenosine monophosphate content presented in white abdomen meat, and the highest equivalent umami concentration value presented in dark meat. The principal component analysis result of electronic tongue and electronic nose showed significant differences in the overall taste and odor characteristics among four group samples. Additionally, 41, 30, 42, and 29 volatile compounds were identified by headspace solid-phase microextraction/gas chromatography-mass spectrometry among white dorsal meat, white abdomen meat, white tail meat, and dark meat of bighead carp, respectively. Based on the data of relative olfactory activity value (ROAV ≥ 1), 12 relative olfactory activity compounds may mainly contribute to the overall odor of bighead carp, including 2-methylbutanal, hexanal, heptanal, (E)-2-octenal, nonanal, dodecanal, undecanal, decanal, 3-methyl-1-pentanol, 1-octen-3-ol, (Z)-2-octen-1-ol, and eucalyptol. Furthermore, according to the Partial Least Squares Discriminant Analysis profile derived from the ROAV of 12 characteristic volatile compounds, significant variations in the odor of different edible parts of bighead carp. Overall, there was a significant difference in taste and odor among different edible parts of bighead carp, and this study may provide useful information for unraveling the flavor characteristics of each edible part of raw bighead carp. PRACTICAL APPLICATIONS: The comprehensive information on taste and odor among different edible parts (white dorsal meat, white abdomen meat, white tail meat, and dark meat) of bighead carp were obtained using liquid chromatography-mass spectrometry, automatic amino acid analyzer, electronic tongue (E-tongue), headspace solid-phase microextraction/gas chromatography-mass spectrometry (HS-SPME/GC-MS), and electronic nose (E-tongue), respectively. This study may provide useful information for unraveling the flavor characteristics of each edible part of raw bighead carp and improving the flavor of bighead carp products.

Prediction of top round beef meat tenderness as a function of marinating time based on commonly evaluated parameters and regression equations

This study investigates the influence of 24-hr marination (with different plant extracts and vinegar) at refrigerated conditions on commonly evaluated physicochemical and textural attributes, including pH, water-holding capacity (WHC), collagen solubility, moisture, drip loss, and shear force values of beef meat. The results reflected the appropriate correlation between each pair and indicated the efficiency of the household marination procedure to acquire more palatability and tender beef meat. Therefore, to predict beef meat tenderness by applying the Warner-Bratzler shear force (WBSF), a strong positive correlation with the drip loss (p < .01) and a notable negative correlation with the moisture content (p < .01) emphasized the importance of moisture improvement and shear force reduction in affecting tenderness of baked beef meat. The regression equations and R-squared values were revealed the favorable correlation between collagen solubility and WHC (y = 0.1035x-0.8431, R 2 = .98) as well as moisture and WBSF (y = -0.3297x + 102.58, R 2 = .99) in marinated beef meat. Electrophoresis patterns of isolated myofibrillar proteins disclosed remarkable degradation of myosin heavy chain (MHC), desmin, actin, and tropomyosin during the first day of aging. The noticeable ultrastructural destruction and connective tissue solubilization were observed by microscopy images. These outcomes were a good tenderness predictor be utilized in retailing and industrial scale.

E-sensing and nanoscale-sensing devices associated with data processing algorithms applied to food quality control: a systematic review

Devices of human-based senses such as e-noses, e-tongues and e-eyes can be used to analyze different compounds in several food matrices. These sensors allow the detection of one or more compounds present in complex food samples, and the responses obtained can be used for several goals when different chemometric tools are applied. In this systematic review, we used Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, to address issues such as e-sensing with chemometric methods for food quality control (FQC). A total of 109 eligible articles were selected from PubMed, Scopus and Web of Science. Thus, we predicted that the association between e-sensing and chemometric tools is essential for FQC. Most studies have applied preliminary approaches like exploratory analysis, while the classification/regression methods have been less investigated. It is worth mentioning that non-linear methods based on artificial intelligence/machine learning, in most cases, had classification/regression performances superior to non-liner, although their applications were seen less often. Another approach that has generated promising results is the data fusion between e-sensing devices or in conjunction with other analytical techniques. Furthermore, some future trends in the application of miniaturized devices and nanoscale sensors are also discussed.

Freshness Quality and Shelf Life Evaluation of the Seaweed Ulva rigida through Physical, Chemical, Microbiological, and Sensory Methods

In Europe, the consumption of seaweeds and derived products has increased in recent years, due to the expansion of Asian cuisine and the emergence of many top-level chefs. Often in collaboration with scientists, many have initiated a new gastronomy using algae. However, little is known about the quality and degree of freshness of seaweeds for direct consumption or fresh use. For this reason, different analytical methods were applied to test sea vegetables and other marine products. These methods included physical (a_w, pH, color, and texture), chemical (total volatile base nitrogen, TVB-N; and trimethylamine, TMA-N) parameters, microbiological count, and sensory evaluation. In this study, freshness quality and shelf life of the green seaweed Ulva rigida (UR) was evaluated during a 12-day period, stored at 4 and 16 °C. The parameters that proved to be most useful for evaluating its freshness were the TVB, TMA, microbiological, and sensory analyses. The physicochemical and microbiological parameters established a shelf life of UR of 6 days for a storage temperature of 16 °C and up to 10 days for a storage temperature of 4 °C. The changes that UR undergoes during its storage from the sensory point of view are more pronounced than those produced from the physicochemical point of view, which can condition its applications.