Other News: Potential nutraceuticals and functional foods

Harvesting of seafood is continuously rising due to its increasing consumption for its many proven health benefits. This in effect has led to the abundance of by-products, as can be seen from the frozen and canned seafood industry in the Asian region where tons of exoskeleton are discarded annually. Commercial processing of aquatic foods requires removal of bones, skin, head, and viscera (by-products), which account for approximately 60-70g/100g of the weight. Most by-products have traditionally been sold cheaply for use in fishmeal production, hauled into the ocean, or dumped on land.

Nowadays, however, fishery by-products are subject to strict environmental regulations due to limited land and increased environmental concerns such as groundwater contamination and foul odor. Compliance with environmental standards and a better understanding of the potential values of processing by-products for a variety of applications have resulted in technological innovations for seafood wastes as nutraceuticals and functional foods. Currently, there has been a growing interest in natural ingredients which are readily available from seafood discards. However, lack of adequate utilization technology to fully convert such wastes into value-added products must be seriously addressed.

Potentials of nutraceuticals and functional foods from fishery by-products

Nutraceutical, a term combining the words "nutrition" and "pharmaceutical," is a broad umbrella term used to describe any food or food product derived from food sources that provides extra health benefits in addition to the basic nutritional value found in foods. Products typically claim to prevent chronic diseases, improve health, delay the aging process, and increase life expectancy.

Oyster shells

Ceramics for water treatment with bactericidal activity was developed from a combination of high-temperature ashing of oyster-shell waste and natural zeolite which turns the white ash into ceramic balls. The ceramic balls inhibit growth of two stains of E. coli, K-12 and O157. The oyster shell ash is mainly calcium carbonate (CaCO3). The high-temperature ashing process converts the CaCO3 to CaO and demonstrates bactericidal effect on E. coli.

Hot-water extract of pulverized oyster shell also produces functional polypeptides that exhibit tyrosinase-inhibitory activity, which is an index for skin-whitening effect. In addition, CaCO3 from oyster shells has been used as a calcium supplement.

Shrimp wastes

In some Asian countries, shrimp head extracts are spray-dried with cyclodextran to produce seafood flavor/seasoning. The digestive enzymes from shrimp wastes have also been found to facilitate fermentation in fish paste. Meanwhile, shrimp and crab shells can be recovered to manufacture chitin, chitosan, and glucosamine. Chitosan has been considered a "fat-binder" and is used for weight management to enhance binding of bile acid and excretion of sterols, thus, lowering cholesterol. It also serves as soluble dietary fiber to improve gastrointestinal function. Chitosan spray is also used in fruits and vegetable production to inhibit crown rot. The spray is also effective in reducing moisture loss during post-harvest handling of fruits and vegetable. Chitin/chitosan has been commercially manufactured from shrimp waste in Thailand, Burma, Vietnam, and Malaysia. The National University of Malaysia's Chitin-Chitosan Research Center has been in existence for more than 20 years, while the Chito-Chem Sdn Bhd is a pioneer in the commercialization of chitosan production for skincare and health products.

Astaxanthin, the chromophore in the carotenoprotein of shrimp shells, can be recovered and emulsified in an antioxidant-containing plant matrix of lignosulfonate and maize starch using beadlet technology. Astaxanthin is mostly used in feeds for aquaculture fishes especially for pigmentation of salmon. It is also an effective antioxidant with efficacy 500 times of vitamin E and up-regulated plasma HDL-cholesterol level.

Fish oils

The health benefit of fish oil and health claims approved by the Food and Drug Administration (FDA) of the US and EU have increased the consumption of fish oil. In Asia, encapsulated fish oil for human consumption has been mainly imported. In this region, fish oil is rendered from fish wastes for feed uses. The fishy odor is still a drawback of fish oil product. Applications of novel technologies, such as supercritical fluid extraction, microencapsulation technology, and enzyme treatment for aroma modification have the potential to improve fish oil quality. Post-harvest handling method, collection strategy to prevent the oxidation of raw material, refining and concentration methods, and the harmonization of fish oil processed from different sources of fisheries and aquaculture species are research areas that need to be pursued to improve product quality of fish oil produced in the Asian region. Cage-cultured cobia is a potential source of fish liver oil. Wastes from cultured eel, catfish and milkfish as well as ocean-caught tuna, sardine, and squid may also be recycled to manufacture fish oil.

Fish protein by-products

Collagen. The skin of tilapia, catfish, and snakehead yields high content of gelatin with high gel strength. Commercial production of gelatin is in the development stage with one small manufacturer in Malaysia. In Thailand, catfish skin is treated with alkaline, then with acid to extract collagen and gelatin. In Taiwan, tilapia skin and scales are separated, hydrolyzed with enzymes and extracted then spray-dried and commercially marketed as "fish collagen peptide" for skincare or as nutraceutical products. Fish collagen may also be made as collagen drink and collagen marshmallow. In Indonesia, a process was established to boil the raw material to extract the collagen from fish bones and to degrease. The extract is then dried and immersed in acid until ossein is obtained. The dried powder of ossein is called collagen.

Hemoproteins. Catfish is bled and 90% of the blood is recovered aided by absorption with chitin. The fish blood by-product is rich in essential amino acids and iron which are used in aquaculture feeds. If the blood collection and the process were subjected to strict hygienic control, the hemoprotein obtained can be used as human dietary supplements.

Muscle protein hydrolysates. Fish meat from fish frame has been made into fish protein concentrate (FPC) and fish protein hydrolysate (FHC). Development of FPC in Malaysia was the first concerted effort in the country to convert the underutilized fish into value-added and readily-acceptable product. The residual clam meat from processing clam essence is hydrolyzed into peptides. The peptides consisting of 3-20 amino acids showed anti-oxidative and anti-hypertensive functions.

Macro-algae

Algae culture has not gained as much emphasis as fish culture. In Taiwan, the crude extract of Sargassum exhibits anti-oxidative and anti-inflammatory activities contributed by its fucose and fucoidan contents. Fucoxanthin and phlorotannins are two major classes of bioactive compounds responsible for the anti-oxidative, anti-obesity, anti-diabetic, anti-inflammatory, and anti-allergic activities. In addition to the brown algae, red algae and green algae may also have potential bioactivities worth exploring.

Issues, prospects and recommendations

Toward the improved utilization of fishery by-products as nutraceuticals and functional foods, effectiveness, sustainability and safety are the key. Scientific/ medical evidence is vital to establish health benefits of nutraceuticals. Nutraceutical is currently not regulated despite efforts for legal and scientific criterion and standards. Hence, labeling/ notification regarding health promoting benefits is an important issue. One major recommendation during the seminar is for Asian countries to have a standard definition and classification of nutraceuticals/functional foods, and a harmonized or common standard. In terms of bioavailability of nutraceuticals, collection techniques to recover bioactive constituents in fishery wastes, novel processing technologies, and absorption rate of supplement product are among the main challenges. Cost effectiveness of research, development and production as against health benefits should also be of prime consideration. Sustainability of raw materials, or availability of alternative raw materials, and other environmental concerns such as foul odor and by-product (raw materials) quality must also be considered, as well as potential market, public acceptability and safety of products.

Process and product development for the preparation of fish collagen from by-products of novel aquaculture species and ocean-caught fishes, and a platform for systematic studies of the biochemical properties, bioactivities, and safety of the collagen peptides are beneficial to stimulate recycling of the waste materials in the region. Methodologies for the screening of underutilized fishery materials with potential economical value and technology transfer from laboratory research to commercial production are likewise vital considerations. Lastly, novel subjects for collaborative research and development, such as isolation of probiotics from fish gut with inhibitory activities against fish diseases, algae culture and identification of bioactive compounds in underutilized algae, must be pursued.

Source: USE THIS LINK

NOTE:
Balai Besar Penelitian dan Pengembangan Pengolahan Produk Kelautan dan Perikanan (Research and Development Center for Marine and Fisheries Product Processing and Biotechnology, BBP4KP) is the research center belonging government to make a product from fisheries and marine material. Many research is doing there include food product and nonfood product.
The term fish processing refers to the processes associated with fish and fish products between the time fish are caught or harvested, and the time the final product is delivered to the customer. Although the term refers specifically to fish, in practice it is extended to cover any aquatic organisms harvested for commercial purposes, whether caught in wild fisheries or harvested from aquaculture or fish farming.
Fish processing can be subdivided into fish handling, which is the preliminary processing of raw fish, and the manufacture of fish products. Another natural subdivision is into primary processing involved in the filleting and freezing of fresh fish for onward distribution to fresh fish retail and catering outlets, and the secondary processing that produces chilled, frozen and canned products for the retail and catering trades.