Fat blocking roles of fish proteins in fried fish cake

Functional proteins through green refining of seafood side streams

Scarcity of nutritive protein is a major global problem, the severity of which is bound to increase with the rising population. The situation demands finding additional sources of proteins that can be both safe as well as acceptable to the consumer. Food waste, particularly from seafood is a plausible feedstock of proteins in this respect. Fishing operations result in appreciable amounts of bycatch having poor food value. In addition, commercial processing results in 50 to 60% of seafood as discards, which consist of shell, head, fileting frames, bones, viscera, fin, skin, roe, and others. Furthermore, voluminous amounts of protein-rich effluents are released during commercial seafood processing. While meat from the bycatch can be raw material for proteinous edible products, proteins from the process discards and effluents can be recovered through biorefining employing upcoming, environmental-friendly, low-cost green processes. Microbial or enzyme treatments release proteins bound to the seafood matrices. Physico-chemical processes such as ultrasound, pulse electric field, high hydrostatic pressure, green solvent extractions and others are available to recover proteins from the by-products. Cultivation of photosynthetic microalgae in nutrient media consisting of seafood side streams generates algal cell mass, a rich source of functional proteins. A zero-waste marine bio-refinery approach can help almost total recovery of proteins and other ingredients from the seafood side streams. The recovered proteins can have high nutritive value and valuable applications as nutraceuticals and food additives.

Effects of Konjac Glucomannan on Oil Absorption and Safety Hazard Factor Formation of Fried Battered Fish Nuggets

The purpose of this study was to investigate the effects of konjac glucomannan (KGM) on oil absorption and the formation of safety hazard factors in fried battered fish nuggets by measuring advanced glycation end products (AGEs) and acrylamide contents. Other physicochemical properties were determined to explore the reason for oil absorption and formation of safety hazard factors. The acrylamide was found mainly in the crust. The addition of 0.8% KGM could significantly reduce the acrylamide content (p < 0.05). For the battered sample, the AGEs content was far lower than the unbattered. The addition of 0.8% KGM could significantly reduce the AGEs content in the inner layer (p < 0.05). The microstructure showed that the sample with 0.8% KGM had the most compact crust. The compact crust reduced oil and malondialdehyde contents. Combined with the other indicators, the inhibitory effect of 0.8% KGM on acrylamide was closely related with the decreased extent of oil oxidation and Maillard reaction in the samples with 0.8% KGM. The inhibitory effect of 0.8% KGM on AGEs might originate from its lower oil content.

Formation of AGEs in fish cakes during air frying and other traditional heating methods

This study investigated the formation of advanced glycation end products (AGEs) in fish cakes under air frying, deep frying, pan frying and baking. The results showed that the AGEs contents on the surface of fish cakes significantly increased with prolonging heating time. The AGEs contents under different methods were following: deep frying > air frying ≈ pan frying > baking. However, the AGEs contents in the interior of fish cakes were hardly influenced by the methods and time. The correlation analysis showed that the AGEs contents were negatively correlated with the moisture content, positively correlated with the yellowness (b*) value, oil content and oxidation products. Additionally, the air-fried fish cake exhibited a denser texture compared to the others, and its colour was similar to the deep-fried ones. Conclusively, the air-fried fish cake showed low oil and AGEs contents, and similar colour to the deep-fried fish cake.

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.

Protein Recovery from Underutilised Marine Bioresources for Product Development with Nutraceutical and Pharmaceutical Bioactivities

The global demand for dietary proteins and protein-derived products are projected to dramatically increase which cannot be met using traditional protein sources. Seafood processing by-products (SPBs) and microalgae are promising resources that can fill the demand gap for proteins and protein derivatives. Globally, 32 million tonnes of SPBs are estimated to be produced annually which represents an inexpensive resource for protein recovery while technical advantages in microalgal biomass production would yield secure protein supplies with minimal competition for arable land and freshwater resources. Moreover, these biomaterials are a rich source of proteins with high nutritional quality while protein hydrolysates and biopeptides derived from these marine proteins possess several useful bioactivities for commercial applications in multiple industries. Efficient utilisation of these marine biomaterials for protein recovery would not only supplement global demand and save natural bioresources but would also successfully address the financial and environmental burdens of biowaste, paving the way for greener production and a circular economy. This comprehensive review analyses the potential of using SPBs and microalgae for protein recovery and production critically assessing the feasibility of current and emerging technologies used for the process development. Nutritional quality, functionalities, and bioactivities of the extracted proteins and derived products together with their potential applications for commercial product development are also systematically summarised and discussed.

Gelling properties of silver carp surimi as affected by different comminution methods: blending and shearing

BACKGROUND

Blending and shearing, two types of comminution methods, are widely used in the manufacturing of surimi-based products. The comminution methods applied are varied to product types and manufacturers. In this study effects of different comminution methods (blending and shearing) on gelling properties of silver carp surimi were investigated.

RESULTS

Regardless of comminution methods, breaking force, penetration distance and water holding capacity of surimi gel significantly increased with comminution duration up to 10 min. As compared with blending, those values under shearing of the same duration were significantly higher. Within 3 min of comminuting whiteness values of gels by shearing were significantly higher than those by blending. Electrophoresis studies showed that comminution method had no obvious effect on protein patterns. Scanning electron microscopy images revealed that more uniform and denser network was formed in the surimi gels made by shearing. Water distribution of the gels made by shearing was obviously more uniform according to magnetic resonance imaging analysis.

CONCLUSION

Our results suggested that with respect to blending, shearing was a better choice to maximize the gelling ability of silver carp surimi, which resulted in the higher values of texture, whiteness and water holding capacity. It could be attributed to the denser three-dimensional network and more uniform water distribution of the surimi gel prepared by shearing. © 2019 Society of Chemical Industry.