The impact of applying natural clinoptilolite (zeolite) on the chemical, sensory and microbiological changes of vacuum packed sardine fillets

Adsorption mechanism of key off-odor compounds of oyster peptide by V-type starch in the solid-phase environment

V-type starch was employed to adsorb key off-odors (heptanal and 1-octen-3-ol) of oyster peptide (OP), and the adsorption mechanism was investigated. The off-odor content was quantified using gas chromatography (GC), and the successful inclusion complexes (ICs) between the key off-odors of OP and V-type starches were detected by X-ray diffraction, differential scanning calorimetry, Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy. In FTIR spectra, the appearance of new peaks and the shifts of characteristic peaks in ICs indicated the successful formation of ICs between V-type starches and heptanal or 1-octen-3-ol. The results of thermodynamic analysis showed that the endothermic peaks of ICs in the range of 113-116 °C corresponded to the formation of V-type II complexes. The GC results suggested that V6a- and V7a-type starches exhibited selective adsorption of heptanal and 1-octen-3-ol, respectively, which was attributed to the size compatibility between starches and guest molecules. Furthermore, the correlation analysis exhibited that the encapsulation efficiency and loading efficiency of V-type starches for heptanal and 1-octen-3-ol were correlated with the enthalpy, short-range order degree and relative crystallinity. The research findings demonstrate the good adsorption effects of V-type starches on characteristic off-odors of OP, which could effectively improve the flavor of OP.

Strategies to reduce fishy odor in aquatic products: Focusing on formation mechanism and mitigation means

Aquatic products, integral to human diets, often bear a distinct fishy odor that diminishes their appeal. Currently, the formation mechanisms of these odoriferous compounds are not fully understood, complicating their effective control. This review aims to provide a comprehensive overview of key fishy compounds, with a focus on their formation mechanisms and innovative methods for controlling fishy odors. Fishy odors in aquatic products arise not only from the surrounding environment but also from endogenous transformations due to lipid autoxidation, enzymatic reactions, degradation of trimethylamine oxide, and Strecker degradation. Methods such as sensory masking, adsorbent and biomaterial adsorption, nanoliposome encapsulation, heat treatment, vacuum treatment, chemical reactions, and biological metabolic transformations have been developed to control fishy odors. Investigating the formation mechanisms of fishy odors will provide solid foundational knowledge that can inspire creative approaches to controlling these unpleasant odors.

Fundamental properties and sustainable applications of the natural zeolite clinoptilolite

This review explores a set of sustainable applications of clinoptilolite, a natural zeolite abundant around the world in different localities. Thanks to its physico-chemical properties this material is extremely versatile for several applications, ranging from environmental catalysis and CO2 removal to industrial and agricultural wastewater purification, aquaculture, animal feeding, and food industry but also medical applications and energy storage systems. Due to the presence of cations in its framework, it is possible to tune the material's features making it suitable for adsorbing specific compounds. Thus, this review aims to provide insight into developing new technologies based on the use of this material that is sustainable, not harmful for humans and animals, naturally abundant, and above all cost-effective. Furthermore, it is intended to promote the use of natural materials in various areas with a view to sustainability and to reduce as far as possible the use of chemicals or other materials whose synthesis process can have a polluting effect on the environment.

Application of natural and synthetic zeolites in the oenological field

Zeolites are crystalline hydrated aluminosilicates, of natural or synthetic origin, characterized by a microporous structure and high adsorption properties. They are employed as soil amendments and fertilizer carriers in agriculture, as catalysts, detergents, adsorbents and molecular sieves in many chemical processes, as well as in water and soil decontamination, and in food processing. They have been also tested in the oenological field for several potential applications; yet an overview on such topic is not still available. The present review summarizes the recent and innovative applications of zeolites in winemaking and supplies a critical discussion about their potential to prevent protein haze, tartrate instability or the appearance of certain defects, like light-struck off-flavour and earthy off-flavours. Further applications of these minerals in the management of winery wastes and in the analytical field are also reviewed. The outcomes of this work evidenced the need of further research on the use of zeolites in oenology for better exploiting their peculiar sorption and exchange properties, selecting the most efficient natural types and improving the performances of the synthetic ones, without disregarding the potential secondary effects of these treatments on wine quality.

The impact of different levels of nisin as a biopreservative agent on the chemical, sensory and microbiological quality of vacuum-packed sea bass (Dicentrarchus labrax) fillets stored at 4 ± 2 °C

Nisin is produced by Lactococcus lactis subsp. lactis and is also known as an antimicrobial agent especially effective against gram-positive bacteria. It has long been used as a preservative in foods and beverages and is generally regarded as safe (GRAS). In the present work, the effects of different concentrations of nisin (0.2, 0.4 and 0.8%) on the sensory, chemical and microbiological quality and shelf-life of vacuum-packed sea bass (Dicentrarchus labrax) fillets were investigated during chilled (4 ± 2 °C) storage. The sensory points for raw and cooked fillets increased with time during the storage period (p < 0.05). The control group, with scores of 9.08, was rejected by panelists on day 12; whereas nisin-treated groups were rejected on day 14 with scores ranging from 9.00-9.17 score. As a result of chemical analyses, lower values (p < 0.05) were obtained from the nisin groups with low oxidative rancidity. Moreover, nisin inhibited microbial growth, which shows antimicrobial activity. Consequently, it was concluded that the application of nisin (especially 0.8%) preserved the organoleptic quality and extended the shelf-life of sea bass fillets.

Effect of feed additive "Ceobalyk" on the biological and microbiological parameters of African sharptooth catfish (Clarias gariepinus)

Aim:

This study aimed to analyze biological and microbiological parameters of Clarias gariepinus bred at Chundzha natural hot spring in the Almaty region of Kazakhstan, a new feed additive, namely, the prebiotic “Ceobalyk.”

Materials and Methods:

Two groups (50 heads each) of fish of the same age were established and kept in specialized rectangular pools of AsylTasEngineering LLP. The experiment lasted 61 days. We used the feed additive “Ceobalyk”, developed based on natural minerals. Feed additive was added to the feed of the experimental group of fish in an amount of 10% per 1 kg of the main diet. Laboratory studies were conducted at the laboratories of the Kazakhstan-Japan Innovation Center. The quality of the fish was studied in accordance with the standards of the Republic of Kazakhstan and interstate standards.

Results:

In biological and microbiological studies of all samples of African sharptooth catfish, which received a new type of feed additive “Ceobalyk”, the pH values of fish meat in the experimental groups were normal and varied in the range from 6.5 to 6.7. When setting up the reaction with copper sulfate, the reaction was positive. During bacterioscopy, there was a noticeable decrease in the number of microbes (2-3 bacteria less) in comparison with the control. An increase in the indices of the absolute body length and body width was observed by the end of the study. The body length in the experimental group was significantly greater (by 2.12% on average) than that in the control group. In the experimental variant, the average weight of fish was 21.8% higher. As a result of organoleptic studies, it was revealed that the musculature of the fish of the experimental groups was dense and elastic; when pressed on the skin with a finger, a fossa did not remain; the smell was specific, fresh. When tested by cooking, the broth was transparent and aromatic.

Conclusion:

This feed additive “Ceobalyk” does not cause deviations in the physiological status of fish and can be used as part of the main diet.

Nonvolatile taste compounds of Shanghai smoked fish: A novel three stages control techniques

In this work, the effect of processing stages including first soaking (FS), frying after first soaking (FFS), and second soaking (SS) on nonvolatile taste compounds of Shanghai smoked fish was investigated using high-performance liquid chromatography (HPLC) and automatic amino acid analyzer. Results showed that the contents of free amino acids (FAAs) ranged from 396.94 to 585.79 mg/100 g and 5'-inosine monophosphate (IMP, as main umami nucleotide) from 215.91 to 284.56 mg/100 g in Shanghai smoked fish, respectively. Moreover, the contents of Glu and Gly as main umami amino acids ranged from 1.64 to 107.32 mg/100 g and 61.61 to 108.88 mg/100 g, respectively. TAV values of IMP, Asp, and Glu in Shanghai smoked fish reached 11.38, 2.73, and 21.46, respectively. The obvious difference could be observed using principal component analysis (PCA) in three processing stages of Shanghai smoked fish. Therefore, probing into the nonvolatile flavor of Shanghai smoked fish could not only enrich the theoretical basis of flavor chemistry in freshwater fish fields, but probe into the formation mechanisms of taste compounds in further study.

Effect of Natural Zeolite (Clinoptilolite) on in vitro Biogenic Amine Production by Gram Positive and Gram Negative Pathogens

The effect of two levels of clinoptilolite (1 and 5%) on the production of biogenic amines (BA) and ammonia (AMN) by Gram positive (Staphylococcus aureus, Enterococcus faecalis, and Listeria monocytogenes) and Gram negative bacteria (Aeromonas hydrophila, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, and Salmonella Parathypi A), in tyrosine decarboxylase broth (TDB) was studied. A. hydrophila and E. coli produced the highest amounts of amines which were 1223.06 and 2627.90 mg/l, respectively. All strains were able to decarboxylate tyrosine to tyramine (TYR) with E. coli being the highest (1657.19 mg/l). A. hydrophila formed >50 mg/l histamine (HIS) while the other strains produced none or very low concentrations (<4 mg/l). Among Gram-positive pathogens, E. faecalis was characterized as the main amine producer (478.23 mg/l). Although dependent on bacterial strain and level used, the natural zeolite clinoptilolite can be used to decrease BA and AMN production by bacterial strains that are of health concern. Practical Applications: Uses of natural prodcuts for biogenic amines inhibition. Clinoptilolite was used to reduce the amounts of amines such as spermine, putrescine, and dopamine produced by pathogenic and spoilage bacteria.

Applications of natural zeolites on agriculture and food production

Zeolites are crystalline hydrated aluminosilicates with remarkable physical and chemical properties, which include losing and receiving water in a reverse way, adsorbing molecules that act as molecular sieves, and replacing their constituent cations without structural change. The commercial production of natural zeolites has accelerated during the last 50 years. The Structure Commission of the International Zeolite Association recorded more than 200 zeolites, which currently include more than 40 naturally occurring zeolites. Recent findings have supported their role in stored-pest management as inert dust applications, pesticide and fertilizer carriers, soil amendments, animal feed additives, mycotoxin binders and food packaging materials. There are many advantages of inert dust application, including low cost, non-neurotoxic action, low mammalian toxicity and safety for human consumption. The latest consumer trends and government protocols have shifted toward organic origin materials to replace synthetic chemical products. In the present review, we summarize most of the main uses of zeolites in food and agruculture, along with the with specific paradigms that illustrate their important role. © 2017 Society of Chemical Industry.

Effect of Mentha spicata L. and Artemisia campestris extracts on the shelf life and quality of vacuum-packed refrigerated sardine (Sardina pilchardus) fillets

The present study investigated the effects of ethanolic extracts obtained from Mentha spicata and Artemisia campestris on the shelf life and the quality of vacuum-packed sardine fillets stored at 3 ± 1°C for a period of 21 days. The three groups were tested were VC, control group; VM, group treated with 1 % mint extract; and VA, group treated with 1 % artemisia extract. The observed shelf life of sardine fillets was 10 days for control samples, whereas the combination of vacuum packaging with mint and artemisia extracts extended the product's shelf life to 17 days. Among the chemical indices determined, the thiobarbituric acid-reactive substances values were significantly lower in VM samples. Total volatile base nitrogen was maintained at low levels in VA samples until 17 days of chilled storage. Results of aerobic plate counts and coliform counts showed the existence of a reduced growth in VA group, whereas lactic acid bacteria did not show a significant difference among groups. Natural extract treatments combined with vacuum packaging showed lower microbiological and chemical indices, indicating that the presence of phenolic compounds in mint and artemisia extracts and the removal of oxygen in the pack retarded lipid oxidation and reduced the growth of microorganisms, which resulted in preventing spoilage and extending the product's shelf life.