Diverse uses of valuable seafood processing industry waste for sustainability: a review

Seafoods are rich in untapped bioactive compounds that have the potential to provide novel ingredients for the development of commercial functional foods and pharmaceuticals. Unfortunately, a large portion of waste or discards is generated in commercial processing setups (50-80%), which is wasted or underutilized. These by-products are a rich source of novel and valuable biomolecules, including bioactive peptides, collagen and gelatin, oligosaccharides, fatty acids, enzymes, calcium, water-soluble minerals, vitamins, carotenoids, chitin, chitosan and biopolymers. These fish components may be used in the food, cosmetic, pharmaceutical, environmental, biomedical and other industries. Furthermore, they provide a viable source for the production of biofuels. As a result, the current review emphasizes the importance of effective by-product and discard reduction techniques that can provide practical and profitable solutions. Recognizing this, many initiatives have been initiated to effectively use them and generate income for the long-term sustainability of the environment and economic framework of the processing industry. This comprehensive review summarizes the current state of the art in the sustainable valorisation of seafood by-products for human consumption. The review can generate a better understanding of the techniques for seafood waste valorisation to accelerate the sector while providing significant benefits.

Potential Cosmetic Active Ingredients Derived from Marine By-Products

The market demand for marine-based cosmetics has shown a tremendous growth rate in the last decade. Marine resources represent a promising source of novel bioactive compounds for new cosmetic ingredient development. However, concern about sustainability also becomes an issue that should be considered in developing cosmetic ingredients. The fisheries industry (e.g., fishing, farming, and processing) generates large amounts of leftovers containing valuable substances, which are potent sources of cosmeceutical ingredients. Several bioactive substances could be extracted from the marine by-product that can be utilized as a potent ingredient to develop cosmetics products. Those bioactive substances (e.g., collagen from fish waste and chitin from crustacean waste) could be utilized as anti-photoaging, anti-wrinkle, skin barrier, and hair care products. From this perspective, this review aims to approach the potential active ingredients derived from marine by-products for cosmetics and discuss the possible activity of those active ingredients in promoting human beauty. In addition, this review also covers the prospect and challenge of using marine by-products toward the emerging concept of sustainable blue cosmetics.

Effects of dual-frequency slit ultrasound on the enzymolysis of high-concentration hydrolyzed feather meal: Biological activities and structural characteristics of hydrolysates

Ultrasound-assisted enzymolysis has been applied to improve conventional enzymolysis, while there are rare reports on the application of ultrasound to high-concentration feather protein enzymolysis. Therefore, the feasibility of dual-frequency slit ultrasound (DFSU) for enzymolysis of high-concentration hydrolyzed feather meal (HFM), as well as the biological activities and structural characteristics of hydrolysates were investigated. The single-factor test was used to optimize the ultrasonic processing parameters: substrate concentration, frequency mode, intermittent ratio, power density, and time. The results showed that protein recovery rate and conversion rate increased by 6.08% and 18.63% under the optimal conditions (200 g/L, 28/80 kHz, 5:2 s/s, 600 W/L, and 3 h) compared with conventional enzymolysis, respectively. The macromolecular proteins in hydrolysates were converted into micromolecular peptides (< 500 Da) when treated by DFSU, and antioxidant activity and angiotensin-I-converting enzyme (ACE) inhibitory activity of hydrolysates were increased. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) images illustrated the microstructure changes of feather protein particles in the ultrasound-assisted enzymatic hydrolysates of HFM (UEH), including more porous, smaller, and more uniform. Additionally, the conformation of protein molecules was significantly affected (P < 0.05), including the increase in free sulfhydryl (SH), the decrease in disulfide bond (SS) and surface hydrophobicity (H₀). Fourier transform infrared (FTIR) spectra analysis further showed that the secondary structure of feather proteins was modified with a reduction in α-helix, β-turn, and β-sheet, while an increase in random coil content was observed. These results indicated that DFSU could be a promising method to enhance high-concentration HFM for preparing peptide-rich hydrolysates with high antioxidant activity and ACE inhibitory activity.

Encapsulation of Salmon Peptides in Marine Liposomes: Physico-Chemical Properties, Antiradical Activities and Biocompatibility Assays

Salmon byproducts (Salmo salar) generated by the food chain represent a source of long-chain polyunsaturated fatty acids (eicosapentaenoic acid (EPA): 20:5n-3; docosahexaenoic acid (DHA): 22:6n-3) and peptides that can be used as supplements in food for nutraceutical or health applications, such as in the prevention of certain pathologies (e.g., Alzheimer’s and cardiovascular diseases). The extraction of polar lipids naturally rich in PUFAs by enzymatic processes without organic solvent (controlled by pH-Stat method), coupled with the production of 1 kDa salmon peptides by membrane filtration, allowed the formulation of nanocarriers. The physicochemical properties of the nanoliposomes (size ranging from 120 to 140 nm, PDI of 0.27, zeta potential between −32 and −46 mV and encapsulation efficiency) were measured, and the bioactivity of salmon hydrolysate peptides was assessed (antioxidant and antiradical activity: ABTS, ORAC, DPPH; iron metal chelation). Salmon peptides exhibited good angiotensin-conversion-enzyme (ACE) inhibition activity, with an IC₅₀ value of 413.43 ± 13.12 µg/mL. Cytotoxicity, metabolic activity and proliferation experiments demonstrated the harmlessness of the nanostructures in these experimental conditions.

Prediction of Bioactive Peptides From Chicken Feather and Pig Hair Keratins Using In Silico Analysis Based on Fragmentomic Approach

BACKGROUND

Keratin is among the most abundant structural proteins of animal origin, however it remains broadly underutilized. <P> Objective: Bioinformatic investigation was performed to evaluate selected keratins originating from mass-produced waste products, i.e., chicken feathers and pig hair, as potential sources of bioactive peptides. <P> Methods: Pepsin, trypsin, chymotrypsin, papain, and subtilisin were used for in silico keratinolysis with the use of "Enzyme(s) action" and fragmentomic analysis of theoretical products was performed using "Profiles of potential biological activity" in BIOPEP-UWM database of bioactive peptides. Bioactivity probability calculation and toxicity prediction of the peptides obtained were estimated using PeptideRanker and ToxinPred tools, respectively. <P> Results: Our results showed that the keratins are a potential source of a variety of biopeptides, including dipeptidyl peptidase IV, angiotensin converting enzyme, prolyl endopeptidase inhibitory and antioxidative. Papain and subtilisin were found to be the most appropriate enzymes for keratin hydrolysis. This study presents possible structures of keratin-derived bioactive peptides that have not been previously described. <P> Conclusion: Our data suggest additional in vitro and in vivo studies to verify theoretical predictions and further investigate the possibility of using keratin-rich waste as a source of peptide nutraceuticals.

Sustainable enzymatic technologies in waste animal fat and protein management

Waste animal fats and proteins (WAFP) are rich in various animal by-products from food industries. On one hand, increasing production of huge amounts of WAFP brings a great challenge to their appropriate disposal, and raises severe risks to environment and life health. On the other hand, the high fat and protein contents in these animal wastes are valuable resources which can be reutilized in an eco-friendly and renewable way. Sustainable enzymatic technologies are promising methods for WAFP management. This review discussed the application of various enzymes in the conversion of WSFP to value-added biodiesel and bioactivate hydrolysates. New biotechnologies to discover novel enzymes with robust properties were proposed as well. This paper also presented the bio-utilization strategy of animal fat and protein wastes as alternative nutrient media for microorganism growth activities to yield important industrial enzymes cost-effectively.

Fish Waste: From Problem to Valuable Resource

Following the growth of the global population and the subsequent rapid increase in urbanization and industrialization, the fisheries and aquaculture production has seen a massive increase driven mainly by the development of fishing technologies. Accordingly, a remarkable increase in the amount of fish waste has been produced around the world; it has been estimated that about two-thirds of the total amount of fish is discarded as waste, creating huge economic and environmental concerns. For this reason, the disposal and recycling of these wastes has become a key issue to be resolved. With the growing attention of the circular economy, the exploitation of underused or discarded marine material can represent a sustainable strategy for the realization of a circular bioeconomy, with the production of materials with high added value. In this study, we underline the enormous role that fish waste can have in the socio-economic sector. This review presents the different compounds with high commercial value obtained by fish byproducts, including collagen, enzymes, and bioactive peptides, and lists their possible applications in different fields.

Effect of porcine plasma hydrolysate on physicochemical, antioxidant, and antimicrobial properties of emulsion-type pork sausage during cold storage

This study evaluated the effect of porcine plasma hydrolysates (PPH) on the physicochemical, antioxidant, and antimicrobial properties of emulsion-type pork sausages. Five levels of PPH were added to sausages (CON, 0 g/kg; T1, 5 g/kg; T2, 10 g/kg; T3, 15 g/kg; and T4, 20 g/kg) and their chemical composition, purge loss, lipid oxidation, microbial count, pH, color, texture, and sensory properties were compared on day 1 and after 4 weeks of cold storage. At 4 weeks of storage, hardness, cohesiveness, and gumminess were highest in T3 (P < 0.05). The peroxide value increased in all treatments during the 4-weeks of storage (P < 0.05); however, it was not significantly different between CON, T2, and T3 (P > 0.05). The total aerobic plate count was the lowest in T4 at week 4 (P < 0.05). Therefore, PPH addition could improve the texture of the emulsion-type pork sausages, and an antimicrobial effect was expected following exposure to at least 20 g/kg PPH.

Challenges and Opportunities in Identifying and Characterising Keratinases for Value-Added Peptide Production

Keratins are important structural proteins produced by mammals, birds and reptiles. Keratins usually act as a protective barrier or a mechanical support. Millions of tonnes of keratin wastes and low value co-products are generated every year in the poultry, meat processing, leather and wool industries. Keratinases are proteases able to breakdown keratin providing a unique opportunity of hydrolysing keratin materials like mammalian hair, wool and feathers under mild conditions. These mild conditions ameliorate the problem of unwanted amino acid modification that usually occurs with thermochemical alternatives. Keratinase hydrolysis addresses the waste problem by producing valuable peptide mixes. Identifying keratinases is an inherent problem associated with the search for new enzymes due to the challenge of predicting protease substrate specificity. Here, we present a comprehensive review of twenty sequenced peptidases with keratinolytic activity from the serine protease and metalloprotease families. The review compares their biochemical activities and highlights the difficulties associated with the interpretation of these data. Potential applications of keratinases and keratin hydrolysates generated with these enzymes are also discussed. The review concludes with a critical discussion of the need for standardized assays and increased number of sequenced keratinases, which would allow a meaningful comparison of the biochemical traits, phylogeny and keratinase sequences. This deeper understanding would facilitate the search of the vast peptidase family sequence space for novel keratinases with industrial potential.

Beyond plucking: Feathers bioprocessing into valuable protein hydrolysates

The livestock production and subsequent processing of meat results in huge quantities of solid waste such as viscera, bones, skin and keratin-rich materials, including feathers, hair, wool, claws and hooves. In particular, the continuous growth of poultry industry generates massive amounts of feathers as major waste material. The conversion of such by-products into materials with increased value has been studied. Hydrothermal, chemical or biological approaches have been investigated to achive effective conversion of highly recalcitrant proteins that are abundant in animal waste, but increasing interest is devoted to the development of biotechnological methods. The processing of feathers and other by-products into protein hydrolysates may have industrial and commercial significance. Therefore, this review comprehensively addresses the postulated applications of hydrolysates obtained from keratinous biomasses. Examples on the utilization of feather hydrolysates as organic soil fertilizers, feed ingredients, cosmetic formulations and biofuel production are described in the literature. Microbial feather hydrolysis can generate bioactive peptides as well. The use of protein-rich waste from meat industry to produce hydrolysates with biological activities constitutes a point of utmost interest for development of functional ingredients with elevated value.

Peptides: Production, bioactivity, functionality, and applications

Production of peptides with various effects from proteins of different sources continues to receive academic attention. Researchers of different disciplines are putting increasing efforts to produce bioactive and functional peptides from different sources such as plants, animals, and food industry by-products. The aim of this review is to introduce production methods of hydrolysates and peptides and provide a comprehensive overview of their bioactivity in terms of their effects on immune, cardiovascular, nervous, and gastrointestinal systems. Moreover, functional and antioxidant properties of hydrolysates and isolated peptides are reviewed. Finally, industrial and commercial applications of bioactive peptides including their use in nutrition and production of pharmaceuticals and nutraceuticals are discussed.

Potential of chicken by-products as sources of useful biological resources

By-products from different animal sources are currently being utilised for beneficial purposes. Chicken processing plants all over the world generate large amount of solid by-products in form of heads, legs, bones, viscera and feather. These wastes are often processed into livestock feed, fertilizers and pet foods or totally discarded. Inappropriate disposal of these wastes causes environmental pollution, diseases and loss of useful biological resources like protein, enzymes and lipids. Utilisation methods that make use of these biological components for producing value added products rather than the direct use of the actual waste material might be another viable option for dealing with these wastes. This line of thought has consequently led to researches on these wastes as sources of protein hydrolysates, enzymes and polyunsaturated fatty acids. Due to the multi-applications of protein hydrolysates in various branches of science and industry, and the large body of literature reporting the conversion of animal wastes to hydrolysates, a large section of this review was devoted to this subject. Thus, this review reports the known functional and bioactive properties of hydrolysates derived from chicken by-products as well their utilisation as source of peptone in microbiological media. Methods of producing these hydrolysates including their microbiological safety are discussed. Based on the few references available in the literature, the potential of some chicken by-product as sources of proteases and polyunsaturated fatty acids are pointed out along with some other future applications.

The oral administration of meat and bone meal-derived protein fractions improved the performance of young broiler chicks

A study was designed to assess the impact of water-soluble proteins and peptides extracted from meat and bone meal (MBM) on broiler chick performance, following their oral delivery during the early post-hatch period. Proteinaceous material was fractionated by size exclusion filtration into weight ranges of <3 kDa (Fraction 1; 0.5 mg protein/mL), 3–100 kDa (Fraction 2; 0.5 mg protein/mL) and >100 kDa (Fraction 3; 0.8 mg protein/mL), which formed the three protein fraction treatments. A total of 1 mL of each of the respective preparations was delivered orally via gavage over 4 days (0.25 µL each day) to Cobb broiler hatchlings. Three control groups: control–unhandled, control–phosphate-buffered saline and control–handled were also included. Chicks were grown to 30 days of age. Feed intake, chick weight gain and feed conversion ratio were determined from day old through to 29 days of age. On Days 10, 16, 23 and 30, the weight of the breast and the small intestine was determined from 10 birds/treatment. For all parameters measured there was no interaction between experimental week and protein fraction treatment. Chicks receiving Fraction 2 had a statistically significant increase in feed intake and weight gain (P = 0.012) compared with the control–unhandled chicks. Chicks receiving Fraction 2 also demonstrated a numerically higher final bodyweight. Mass spectrometric analysis of all three fractions revealed that they each contained a wide array of proteinacious material. The results of this study suggests the likelihood that protein or protein-derived fragment components within the 3–100 kDa molecular weight range of MBM can generate improvements in broiler chick production, and thus promote the need for further research to identify the specific protein(s) responsible for the observed positive growth effects.

Marine fish-derived bioactive peptides as potential antihypertensive agents

Hypertension is the most widespread risk factor for many serious cardiovascular diseases. Angiotensin-converting enzyme (ACE) plays a crucial role in cardiovascular physiological regulation by converting angiotensin I to a potent vasoconstrictor, angiotensin II. Hence, the inhibition of ACE is a key target for antihypertensive activity. Recently, potent antihypertensive peptides have been purified widely by enzymatic hydrolysis of muscle protein, skin collagen, and gelatin of many different kinds of marine fishes. Marine fish-derived bioactive peptides can be developed as antihypertensive components in functional foods or nutraceuticals. This contribution presents an overview of the ACE inhibitory peptides derived from marine fishes and discusses their future prospects to be used as potential drug candidates for preventing and treating high blood pressure.

Utilization of byproducts and waste materials from meat, poultry and fish processing industries: a review

India is bestowed with vast livestock wealth and it is growing at the rate of 6% per annum. The contribution of livestock industry including poultry and fish is increasing substantially in GDP of country which accounts for >40% of total agricultural sector and >12% of GDP. This contribution would have been much greater had the animal by-products been also efficiently utilized. Efficient utilization of by-products has direct impact on the economy and environmental pollution of the country. Non-utilization or under utilization of by-products not only lead to loss of potential revenues but also lead to the added and increasing cost of disposal of these products. Non-utilization of animal by-products in a proper way may create major aesthetic and catastrophic health problems. Besides pollution and hazard aspects, in many cases meat, poultry and fish processing wastes have a potential for recycling raw materials or for conversion into useful products of higher value. Traditions, culture and religion are often important when a meat by-product is being utilized for food. Regulatory requirements are also important because many countries restrict the use of meat by-products for reasons of food safety and quality. By-products such as blood, liver, lung, kidney, brains, spleen and tripe has good nutritive value. Medicinal and pharmaceutical uses of by-product are also highlighted in this review. Waste products from the poultry processing and egg production industries must be efficiently dealt with as the growth of these industries depends largely on waste management. Treated fish waste has found many applications among with which the most important are animal feed, biodiesel/biogas, dietectic products (chitosan), natural pigments (after extraction) and cosmetics (collagen). Available information pertaining to the utilization of by-products and waste materials from meat, poultry and fish and their processing industries has been reviewed here.

Isolation, purification and characterization of antioxidant peptidic fractions from a bovine liver sarcoplasmic protein thermolysin hydrolyzate

Sarcoplasmic proteins isolated from bovine livers were hydrolyzed using the enzyme thermolysin at 37°C for 2h. The hydrolyzates were filtered through molecular weight cut off membranes (MWCO) and filtrates were obtained. The water activity (a(w)) of unhydrolysed sarcoplasmic protein, full hydrolyzates, 10-kDa and 3-kDa filtrates were below the limit necessary for microbial growth. The antioxidant activities of both filtrates and fractions were assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity assay, the ferric ion reducing antioxidant power (FRAP) assay and the Fe(2+) chelating ability assay. RP-HPLC was used for purification of the full hydrolyzates, the 10-kDa and the 3-kDa filtrates. The peptidic content of the full hydrolyzates, the 10-kDa and the 3-kDa filtrates were assessed using the Dumas method and peptide contents of each fraction were characterized using electrospray quadrupole time-of-flight (ESI-Q-TOF) mass spectrometry with the resultant spectrum analysed using the software programmes Protein Lynx Global Server 2.4. and TurboSEQUEST. Similarities between the amino acid composition of characterized peptides from each fraction and previously reported antioxidant peptides were found. This study demonstrates that meat by-product such as liver can be utilised as raw material for the generation of bioactive peptides with demonstrated antioxidant activities in vitro using the enzyme thermolysin. It is significant as it presents a potential opportunity for meat processors to use their waste streams for the generation of bioactive peptides for potential functional food use.