Fish Quality Index Method: Principles,weaknesses, validation,and alternatives—A review

Fish is a high nutritional value matrix of which production and consumption have been increasing in the last years. Advancements in the efficient evaluation of freshness are essential to optimize the quality assessment, to improve consumer safety, and to reduce raw material losses. Therefore, it is necessary to use rapid, nondestructive, and objective methodologies to evaluate the quality of this matrix. Quality Index Method (QIM) is a tool applied to indicate fish freshness through a sensory evaluation performed by a group of assessors. However, the use of QIM as an official method for quality assessment is limited by the protocol, sampling size, specificities of the species, storage conditions, and assessor's experience, which make this method subjective. Also, QIM may present divergences regarding the development of microorganisms and chemical analysis. In this way, novel quality evaluation methods such as electronic noses, electronic tongues, machine vision system, and colorimetric sensors have been proposed, and novel technologies such as proteomics and mitochondrial analysis have been developed. In this review, the weaknesses of QIM were exposed, and novel methodologies for quality evaluation were presented. The consolidation of these novel methodologies and their use as methods of quality assessment are an alternative to sensory methods, and their understanding enables a more effective fish quality control.     

Fish liver and seagull eggs,vitamin D‐rich foods with a shadow: Results from the Norwegian Fish and Game Study

Scope Fish liver, fish liver oil, oily fish and seagull eggs have been major sources of vitamin D for the coastal population of Norway. They also provide dioxin and polychlorinated dioxin‐like compounds (dl‐compounds), which may interfere with vitamin D homeostasis. We investigated whether serum 25‐hydroxyvitamin D (25(OH)D) might be compromised by concomitant intake of dl‐compounds. Methods and results We studied 182 adults participating in the Norwegian Fish and Game Study. Participants who consumed fish liver and/or seagull eggs had higher dl‐compound intake and blood concentrations than non‐consumers (p < 0.001). Vitamin D intake was higher (p < 0.001), whereas serum 25(OH)D was lower (p = 0.029) in consumers than in non‐consumers. Among non‐consumers, vitamin D intake was associated with serum 25(OH)D (β=1.06; 95% CI: 0.48, 1.63). This association was weaker among consumers (β = 0.52; 95% CI: ?0.05, 1.08), but strengthened when adjusted for retinol intake (β = 0.66; 95% CI: 0.12, 1.21). The association between vitamin D intake and serum 25(OH)D did not seem to be compromised by intake of dl‐compounds. Conclusion To secure adequate vitamin D status while keeping the intake of dioxins and dl‐polychlorinated biphenyls low, a healthy diet should include both supplemental vitamin D and oily fish. Despite high nutrient content, dietary fish liver and seagull eggs should be restricted, due to dl‐compounds and possible vitamin A‐D antagonism.     

Enzymatic Hydrolysate fo Fish,Spray-Dried Fish Solubles,and Soybean Protein Concentrate in Milk Replacers for Calves,

Holstein calves (120) were fed milk replacers as the only nutrients from 4 to 46 days of age. All milk replacers contained 20% crude protein and differed in protein source: 1) 100% milk protein; 2) 67% milk protein, 33% soybean protein concentrate; 3) 67% milk protein, 33% enzymatic hydrolysate of fish; 4) 67% milk protein, 16.5% soybean protein concentrate, 16.5% enzymatic hydrolysate of fish; 5) 67% milk protein, 16.5% soybean protein concentrate, 16.5% spray-dried fish solubles; 6) 67% milk protein, 24.75% soybean protein concentrate, 8.25% spray-dried fish solubles.Substitution up to 33% of dietary protein with soybean protein concentrate or combinations of soybean, enzymatic hydrolysate of fish, or spray-dried fish solubles produced 14% lower weight gains than all milk protein, but 33% replacement with enzymatic hydrolysate of fish produced 27% lower weight gains. Feed consumed per kilogram of gain was least for all milk, most for 33% fish hydrolysate, and intermediate for other rations. Scour scores did not differ between diets.     

Fish Allergy: Fish and Products Thereof

ABSTRACT: Allergy to fish is a common cause of IgE‐mediated food allergic reactions especially in geographic regions where fish is an important dietary component. Fish allergy is estimated to affect 0.4% of the total population in the United States. All species of fish are believed to be allergenic, but allergic reactions to fish reported in the medical literature are most commonly caused by cod and salmon. The major allergen in fish is a naturally occurring muscle protein called parvalbumin. Some evidence exists of allergic reactions to other fish proteins including collagen. This review addresses fish allergy and fish‐derived ingredients, namely gelatin, isinglass, fish maws, ice‐structuring protein, fish oil, and Worcestershire sauce.     

Cholesterol Oxidation in Fish and Fish Products

Fish and fish products are important from a nutritional point of view due to the presence of high biological value proteins and the high content of polyunsaturated fatty acids, especially those of the n‐3 series, and above all eicosapentaenoic acid and docosahexaenoic acid. However, these important food products also contain significant amounts of cholesterol. Although cholesterol participates in essential functions in the human body, it is unstable, especially in the presence of light, oxygen, radiation, and high temperatures that can cause the formation of cholesterol oxidation products or cholesterol oxides, which are prejudicial to human health. Fish processing involves high and low temperatures, as well as other methods for microbiological control, which increases shelf life and consequently added value; however, such processes favor the formation of cholesterol oxidation products. This review brings together data on the formation of cholesterol oxides during the preparation and processing of fish into food products which are recognized and recommended for their nutritional properties.     

Salting and Drying Fish. 3. Diffusion of Water

SUMMARY– Drying of salted fish was studied in the falling rate period. It was found that this period consisted of two distinct phases, each of which was characterized by a Fickian diffusion coefficient. The coefficient for the first phase was, in all cases, greater than that for the second phase. The effect, on both diffusion coefficients, of the following variables was studied: degree of salting, drying temperature, and degree of hydration of -the muscle (varied by addition of acid, base and sodium trypolyphosphate to the muscle). The first diffusion coefficient was found to increase, pass through a maximum, and then decrease with degree of salting. The second coefficient was found to decrease with degree of salting within the range for which it was determined.
The first diffusion coefficient was found to be directly correlated with the degree of hydration of the muscle; a plot of the coefficient versus water content of the muscle (expressed as pounds of water per pound of bone-dry solids) yielded a straight line, the regression equation of which was found to be D = 0.16W + 0.09, where D is the diffusion coefficient in cm²/sec × 10⁵ and W is the water content. Variations in the diffusion coefficient due to degree of salting and due to addition of acid, base, and phosphate could be explained by the hydration-dependence of the coefficient. The temperature variation of both coefficients was found not to be great.     

Fish scale collagen. Preparation and partial characterization

Fish scale was decalcified and disaggregated and then collagen was prepared by limited pepsin digestion. The yields of collagens were very high on a dry weight basis; sardine 50.9%, red sea bream 37.5% and Japanese sea bass 41.0%, respectively. These scale collagens were heterotrimers with a chain composition of (α1)₂α2. Although the denaturation temperature of the collagen was lower than land animal collagen, fish scales will have potential as an important collagen source for use in various industries.     

鱼皮明胶的制备、特性及应用

由于传统哺乳动物明胶带来的传染病问题以及穆斯林、犹太等特定消费者的需求,鱼明胶受到了很大的关注。本文叙述了鱼皮明胶的制备方法,并在分析其结构的基础上,论述了鱼皮明胶的胶凝特性、成膜性和感官特性,同时对鱼皮明胶在食品中的应用作了简单介绍。     

Nutrients and Chemical Pollutants in Fish and Shellfish. Balancing Health Benefits and Risks of Regular Fish Consumption

Dietary patterns and lifestyle factors are clearly associated with at least five of the ten leading causes of death, including coronary heart disease, certain types of cancer, stroke, non-insulin insulin-dependent diabetes mellitus, and atherosclerosis. Concerning specifically fish and seafood consumption, its beneficial health effects in humans are clearly supported by an important number of studies performed in the last 30 years. These studies have repeatedly linked fish consumption, especially those species whose contents in omega-3 fatty acids are high, with healthier hearts in the aging population. The nutritional benefits of fish and seafood are also due to the content of high-quality protein, vitamins, as well as other essential nutrients. However, a number of studies, particularly investigations performed in recent years, have shown that the unavoidable presence of environmental contaminants in fish and shellfish can also mean a certain risk for the health of some consumers. While prestigious international associations as the American Heart Association have recommended eating fish at least two times (two servings a week), based on our own experimental results, as well as in results from other laboratories, we cannot be in total agreement with that recommendation. Although a regular consumption of most fish and shellfish species should not mean adverse health effects for the consumers, the specific fish and shellfish species consumed, the frequency of consumption, as well as the meal size, are essential issues for adequately balancing the health benefits and risks of regular fish consumption.     

Fish, fishing, and pollutant reduction in the Baltic Sea

The Baltic Sea is heavily polluted yet supports major commercial fisheries for cod (Gadus morhua), herring (Clupea harengus), and sprat (Sprattus sprattus). Emissions of persistent organic pollutants, such as polychlorinated biphenyls (PCBs) and DDT, were high during the 1960s and 1970s, and concentrations in fish and other fauna are still significant. Several models of the fluxes of these pollutants among the water, sediment, and atmosphere have been developed, but these generally omit the roles of fish and fisheries. We show that the standing stock of the most abundant fish species in the Baltic Sea was a sink for 260 kg of PCBs in the late 1980s to early 1990s and that the fishery removed as much or more PCB (31 kg yr(-1))than other budget components (e.g., degradation in the water column). Accounting for fish and fisheries could increase our understanding of the fluxes of pollutants, and banning the discard of highly contaminated organs such as cod liver could be part of the pollution management.     

Fish protein hydrolysates: production, biochemical, and functional properties

Considerable amounts of fish processing byproducts are discarded each year. By developing enzyme technologies for protein recovery and modification, production of a broad spectrum of food ingredients and industrial products may be possible. Hydrolyzed vegetable and milk proteins are widely used food ingredients. There are few hydrolyzed fish protein foods with the exception of East Asian condiments and sauces. This review describes various manufacturing techniques for fish protein hydrolysates using acid, base, endogenous enzymes, and added bacterial or digestive proteases. The chemical and biochemical characteristics of hydrolyzed fish proteins are discussed. In addition, functional properties of fish protein hydrolysates are described, including solubility, water-holding capacity, emulsification, and foam-forming ability. Possible applications of fish protein hydrolysates in food systems are provided, and comparison with other food protein hydrolysates where pertinent.     

Application of the SureTect Detection Methods for <Emphasis Type="Italic">Listeria monocytogenes</Emphasis> and <Emphasis Type="Italic">Listeria</Emphasis> spp. in Meat,Dairy, Fish,and Vegetable Products

The aim of this study was to evaluate the application of the Listeria monocytogenes and Listeria spp. SureTect detection methods for a rapid and sensitive detection in an ample range of food products: raw pork and poultry meat, Spanish chorizo, pate, smoked salmon, raw sheep milk cured cheese, and ready-to-eat lettuce salad. The combination of a 24-h enrichment in the 24 Listeria Enrichment Broth (LEB) coupled to a rapid bacterial DNA extraction and real-time polymerase chain reaction (RTi-PCR) using the specific SureTect methods detected down to 2–6 L. monocytogenes CFU per sample in less than 27 h on the food categories tested. Furthermore, the applicability of L. monocytogenes and Listeria spp. SureTect detection methods in real samples was assessed using 303 food samples, obtaining at least the same analytical performance as the international reference method ISO 11290-1.