Anti-freeze effect of Enoki mushroom extract on the quality preservation of frozen whipped cream

Probing the interaction between biomolecules under sub-zero temperature conditions by electrophoresis in ice grain boundaries

BACKGROUND

Psychrophiles can survive under cryogenic conditions because of various biomolecules. These molecules interact with cells, ice crystals, and lipid bilayers to enhance their functionality. Previous studies typically measured these interactions by thawing frozen samples and conducting biological assays at room temperature; however, studying these interactions under cryogenic conditions is crucial. This is because these biomolecules can function at lower temperatures. Therefore, a platform for measuring chemical interactions under sub-zero temperature conditions must be established.

RESULTS

The chemical interactions between biomolecules under sub-zero temperature conditions were evaluated within ice grain boundaries with a channel-like structure, which circumvents the need for thawing. An aqueous solution of sucrose was frozen within a microfluidic channel, facilitating the formation of freeze-concentrated solutions (FCSs) that functioned as size-tunable electrophoretic fields. Avidin proteins or single-stranded DNA (ssDNA) were introduced into the FCS in advance. Probe micro/nanospheres whose surfaces were modified with molecules complementary to the target analytes were introduced into the FCS. If the targets have functionalities under sub-zero temperature conditions, they interact with complementary molecules. The chemical interactions between the target molecules and nanospheres led to the aggregation of the particles. The size tunability of the diameter of the FCS channels enabled the recognition of aggregation levels, which is indicative of interaction reactivity. The avidin-biotin interaction and ssDNA hybridization served as models for chemical interactions, demonstrating interactivity under sub-zero temperature conditions. The results presented herein suggest the potential for in situ measurement of biochemical assays in the frozen state, elucidating the functionality of bio-related macromolecules at or slightly below 0 °C.

SIGNIFICANCE

This is the first methodology to evaluate chemical interactions under sub-zero temperature conditions without employing the freeze-and-thaw process. This method has the advantage of revealing the chemical interactions only at low temperatures. Therefore, it can be used to screen and evaluate the functionality of cryo-related biomolecules, including cold-shock and antifreeze proteins.

Effects of Flammulina velutipes polysaccharide with ice recrystallization inhibition activity on the quality of beef patties during freeze-thaw cycles: An emphasis on water status and distribution

The antifreeze activity of Flammulina velutipes polysaccharide (FVP) autoclave-extracted with dilute alkaline and effects of FVP on moisture status, size of ice crystals, physical and chemical characteristics of beef patties during repeated freeze-thaw (F-T) cycles were investigated. Results showed that FVP exhibited ice recrystallization inhibition activity and was able to alter the onset freezing/melting temperature of beef patties. 0.01% FVP significantly alleviated (P < 0.05) the decrement in water holding capacity by inhibiting water migration, restraining the mobility of water, and reducing the size of ice crystals of beef patties during the repeated F-T cycles. In addition, FVP could effectively inhibited oxidation reaction and protein aggregation of beef patties with significant decreases in TBARS value, protein turbidity, contents of total sulfhydryl and carbonyl of myofibrillar protein, and an increase in protein solubility during the repeated cycles. These results suggest FVP could be developed to be a promising cryoprotectant in frozen patties.

A comprehensive review of the application of ultrasonication in the production and processing of edible mushrooms: Drying, extraction of bioactive compounds, and post-harvest preservation

Edible mushrooms are high in nutrients, low in calories, and contain bioactive substances; thus, they are a valuable food source. However, the high moisture content of edible mushrooms not only restricts their storage and transportation after harvesting, but also leads to a shorter processable cycle, production and processing limitations, and a high risk of deterioration. In recent years, ultrasonic technology has been widely applied to various food production operations, including product cleaning, post-harvest preservation, freezing and thawing, emulsifying, and drying. This paper reviews applications of ultrasonic technology in the production and processing of edible mushrooms in recent years. The effects of ultrasonic technology on the drying, extraction of bioactive substances, post-harvest preservation, shelf life/preservation, freezing and thawing, and frying of edible mushrooms are discussed. In summary, the application of ultrasonic technology in the edible mushroom industry has a positive effect and promotes the development of this industry.

Effect of antifreeze proteins on the freeze-thaw cycle of foods: fundamentals, mechanisms of action, current challenges and recommendations for future work

Freezing is widely used in food preservation, but if not carried out properly, ice crystals can multiply (nucleation) or grow (recrystallization) rapidly. This also affects thawing, causing structural damage and affecting overall quality. The objective of this review is to comprehensively study the cryoprotective effect of antifreeze proteins (AFPs), highlighting their role in the freeze-thaw process of food. The properties of AFPs are based on their thermal hysteresis capacity (THC), on the modification of crystal morphology and on the inhibition of ice recrystallization. The mechanism of action of AFPs is based on the adsorption-inhibition theory, but the specific role of hydrogen and hydrophobic bonds/residues and structural characteristics is also detailed. Because of the properties of AFPs, they have been successfully used to preserve the quality of a wide variety of refrigerated and frozen foods. Among the limitations of the use of AFPs, the high cost of production stands out, but currently there are solutions such as the use the production of recombinant proteins, cloning and chemical synthesis. Although in vitro, in vivo and human studies have shown that AFPs are non-toxic, their safety remains a matter of debate. Further studies are recommended to expand knowledge about AFPs, to reduce costs in their large-scale production, to understand their interaction with other food compounds and their possible effects on the consumer.

A multiplicative approach to optimize the consumer properties of quick-frozen semifinished products from cultivated champignons

It is possible to maximise the consumer properties of grown fruit and vegetable products, significantly reduce their losses during the life cycle, and satisfy the public demand for products ready for consumption by using different preservation methods, particularly freezing. It has been found that the freezing of mushrooms without pretreatment does not provide a high-quality finished product. It justifies the expediency of mushroom pretreatment before freezing to stabilize their consumer properties. The inhibition effect of high temperatures on the oxidoreductase activity has been confirmed, ensuring the high preservation of cultivated champignons' natural color and consistency. A quasimetric assessment of the quality of quick-frozen cultivated mushrooms was performed, and the optimal heat treatment parameters were determined. Before freezing, blanched mushrooms' efficiency with polysaccharides has been scientifically proved. Rational concentrations and types of polysaccharides for mushroom processing have been determined. It has been established that blanching champignons in 0.1% citric acid solution followed by xanthan gum (0.2%), guar gum (0.1%), and lamidan (0.1%) processing ensure stability of consumer properties of quick-frozen semifinished products made of cultured champignons. After defrosting, they have an attractive appearance, natural light brown colour, elastic consistency, well-expressed mushroom flavour, and harmonious taste.