Pathway-oriented action of dietary essential oils to prevent muscle protein oxidation and texture deterioration of farmed rainbow trout

Abstract

Recently, great attention has been directed towards the use of essential oils from aromatic plants as antimicrobials and antioxidant in food matrix. Fish is well known to be a high perishable food. Indeed, fish muscle is susceptible to suffer protein and lipid oxidation during frozen storage, which can lead to the development of softening and undesirable volatile molecules. However, the possible inclusion of essential oils in fish feed for preserving fish flesh quality during storage is still unclear. For this reason, the potential protective effects of the incorporation of a dietary essential oil constituted by eucalyptol, carvacrol and thymol, to rainbow trout’s (Oncorhynchus mykiss) feed were here investigated. Frozen fish fillets resulting from trout fed the essential oil showed a significant protection of specific muscle proteins against the oxidation produced during frozen storage at –10ºC for 6 months. Essential oil-enriched feed decreased carbonylation of specific myofibrillar (α-actinins-1 and -3, myosin heavy chain, myomesin-1, pyruvate kinase, tropomyosin, troponin-T and actin) and sarcoplasmic proteins (glycogen phosphorylase, creatine kinase, fructose-bisphosphate aldolase A and phosphoglycerate mutase 2). Essential oils also increased actin stability and preserved muscle protein solubility and water holding capacity. In addition, essential oils inhibited the onset of lipid oxidation and rancidity, resulting in frozen fish with superior textural quality and sensory scores. As a final conclusion, the inclusion of essential oils in farmed rainbow trout feed is largely efficient for increasing fish quality and shelf life during frozen storage, mainly through a selective-antioxidant effect on muscle proteins.

Effect of the dietary supplementation based on essential oils on the quality of gilthead seabream

“…Regarding adhesiveness, a slight but significant difference was observed for diet A, producing slightly higher values than diet C. This was also observed in a study carried out in rainbow trout fillets (Santos et al, 2019), in which adhesiveness was also significantly affected by the enrichment of feed with essential oils. These authors observed a particular inhibition of protein oxidation, especially notable in the myofibrillar fraction, and protection of the loss of protein solubility, together preventing flesh changes in adhesiveness.…”

“…Regarding adhesiveness, a slight but significant difference was observed for diet A, producing slightly higher values than diet C. This was also observed in a study carried out in rainbow trout fillets (Santos et al, 2019), in which adhesiveness was also significantly affected by the enrichment of feed with essential oils.…”

“…Finally, there was an upward trend in the case of gumminess, this parameter increasing with time, although only statistically significant in the case of diet A. Santos et al., (2019) found that gumminess in rainbow trout fillets increased during the first weeks of storage and then remained constant during the rest of frozen storage.…”

Analysis of Protein Oxidation in Food and Feed Products

“…In peanut-based milk substitutes, where peanut proteins act as emulsifiers, protein oxidation has a negative impact on emulsion stability . Protein oxidation may lead to increased toughness and decreased juiciness of meat, whereas the consequences on water-holding capacity and drip loss of meat have not yet been fully understood. − In the muscle proteins of fish fed with added essential oils, protein oxidation was reduced and the water-holding capacity of the frozen fillets slightly increased . Many of the effects are related to oxidation-induced protein cross-linking, e.g., by cystine or dityrosine.…”

Effects of Dietary Supplementation with Honeybee Pollen and Its Supercritical Fluid Extract on Immune Response and Fillet’s Quality of Farmed Gilthead Seabream (Sparus aurata)

“…Dietary intervention with natural extracts, essential oils, and plant by-products was studied even to enhance meat quality and stability during storage, according to the consumer's demand for "natural animal feeding". A valuable example was recently proposed by Santos and colleagues [10], who found out that an essential oil blend, administrated to rainbow trout, asserted specific protection against lipid and protein oxidation of fish fillets stored at -10 • C for 6 months [10]. Besides, gilthead sea bream (Sparus aurata) shelf life was increased by supplementing the diet with thymol due to the reduction of spoilage and lipid oxidation damages [11].…”