Functional and antioxidative properties of protein hydrolysates from Cape hake by‐products prepared by three different methodologies

BACKGROUND: The production of fish protein hydrolysates (FPH) is a convenient technology for upgrading fish by‐products. The aim of this work was to study three different methods of FPH preparation from Cape hake by‐products to improve yield and quality. Functional and antioxidative properties of all FPHs were determined. RESULTS: The protein content of hake FPH was in the range 807–860 g kg^?1 and the degree of hydrolysis was between 19% and 22%. The maximum yield (71.9%) was achieved by methodology B but the hydrolysate was darker. The peptide profile of all FPHs was very similar. FPH prepared by methodology C had significantly higher emulsifying activity index and hydrolysate prepared by methodology B had the highest foaming capacity. The solubility of FPH was in the range 71–76% and increased the water‐holding capacity of minced fish by about 9%. The fractionation of FPH obtained by methodologies A and B allowed concentrating peptides with higher radical scavenging activity and reducing power. CONCLUSION: The properties of the FPH prepared indicated that they can be used in food systems as natural additives, particularly to improve their water‐holding capacity. © 2012 Society of Chemical Industry     

Properties of hydrolysed saithe protein isolates prepared via pH shift process with and without dewatering

Fish protein hydrolysates (FPH) possess various bioactivities making them a desirable ingredient in health foods. Saithe is an underutilized fish species and an excellent candidate for FPH. To produce high quality FPH removing undesirable components prior to the hydrolysis process is preferred and possible via the pH-shift process. The objective was to produce and investigate the properties of hydrolyzed protein isolates produced from minced saithe trimmings. Saithe trimmings were minced, homogenized in water and subjected to two variations of a pH shift process with (A) and without (B) dewatering. The latter process has the advantage of being less complicated and less expensive which is beneficial to the industry. Both systems were adjusted to 3% protein, pH 8 and 45 °C and subjected to enzyme hydrolysis. Both hydrolysis processes led to almost identical SDS-page peptide makeup. Both FPHs had similar antioxidative activities evaluated using oxygen radical absorbance capacity (ORAC), iron chelation ability and (DPPH) radical scavenging ability assays. FPH from process A had significantly higher ACE inhibition ability compared to FPH from process B.These results demonstrate that saithe FPH has good antioxidative activities and a strong ability to inhibit ACE, and may thus have a potential as a bioactive food ingredient.     

Enzymatic hydrolysis of blue whiting (Micromesistius poutassou); functional and bioactive properties

Functional and biochemical properties of fish protein hydrolysates (FPH) from blue whiting (BW) were studied. FPH (2.5%, 5%, 10%, and 15% degree of hydrolysis [DH]) were made from isolated proteins from headed and gutted BW with Alcalase 2.4 L. The properties of dried BW mince and protein isolate compared to 4 reference proteins (soy and milk protein) were studied: color, solubility, water-holding capacity (WHC), oil-binding capacity (OBC), emulsion capacity (EC), and emulsion stability (ES). The angiotensin I-converting enzyme (ACE) inhibitory activities of the soluble fraction of BW powders were also investigated. Furthermore, the products were characterized by analyzing their chemical composition. Chemical composition, solubility, OBC, and EC of the BW powders was significantly (P < 0.05) different with different DH, while color, ES, and WHC were not significantly (P > 0.05) different. Salt content of the FPH was high (4% to 19%) and increased with increased DH. Protein solubility varied from 10% to 70% and increased with increased DH. WHC of the FPH was around 97% and was higher than that of all the reference proteins tested. OBC decreased with increased DH (from 3.5 to 2.1 g oil/g protein) and was higher than OBC of the soy and milk proteins (1.6 to 1.9 g oil/g protein). EC of FPH was similar or lower than the reference proteins. ES of FPH (60% to 90%) was similar to or lower than soy and whey proteins (60% to 98%) but higher than casein (20%). ACE inhibition activity increased as DH was increased. Practical Application: The results from this study demonstrate that a functional bioactive hydrolysate can be produced from BW, which is an underutilized fish species, and may aid the industry in better utilizing this raw material. The novelty of this research was the use of BW as a raw material where the protein has been isolated with the pH shift method. Furthermore, it was novel that bioactivity and functionality was measured in the same samples.     

Fish Protein Hydrolysates: Application in Deep‐Fried Food and Food Safety Analysis

Four different processes (enzymatic, microwave‐intensified enzymatic, chemical, and microwave‐intensified chemical) were used to produce fish protein hydrolysates (FPH) from Yellowtail Kingfish for food applications. In this study, the production yield and oil‐binding capacity of FPH produced from different processes were evaluated. Microwave intensification significantly increased the production yields of enzymatic process from 42% to 63%. It also increased the production yields of chemical process from 87% to 98%. The chemical process and microwave‐intensified chemical process produced the FPH with low oil‐binding capacity (8.66 g oil/g FPH and 6.25 g oil/g FPH), whereas the microwave‐intensified enzymatic process produced FPH with the highest oil‐binding capacity (16.4 g oil/g FPH). The FPH from the 4 processes were applied in the formulation of deep‐fried battered fish and deep‐fried fish cakes. The fat uptake of deep‐fried battered fish can be reduced significantly from about 7% to about 4.5% by replacing 1% (w/w) batter powder with FPH, and the fat uptake of deep‐fried fish cakes can be significantly reduced from about 11% to about 1% by replacing 1% (w/w) fish mince with FPH. Food safety tests of the FPH produced by these processes demonstrated that the maximum proportion of FPH that can be safely used in food formulation is 10%, due to its high content of histamine. This study demonstrates the value of FPH to the food industry and bridges the theoretical studies with the commercial applications of FPH.     

Endogenous Proteases in Pacific Whiting (Merluccius productus) Muscle as A Processing Aid in Functional Fish Protein Hydrolysate Production

A fish protein hydrolysate (FPH) from Pacific whiting (Merluccius productus) muscle was produced by autolysis of a minced homogenate (8% protein) at pH 7.0 and 60°C, where maximum endogenous proteolytic activity was detected. FPH production was controlled by the pH stat method, yielding a 4.43% degree of hydrolysis after 1 h of autolysis. Upon autolytic processing, 28.9 ± 0.7% of the total protein was found in the soluble fraction. FPH was 100% soluble at pH 7.0 and 10.0 and was less soluble at pH 4 (82.5%, P ≤ 0.05). FPH showed better emulsifying properties than sodium caseinate (SCA) at pH 4.0 (P ≤ 0.05), but had a lower foaming capacity (P ≤ 0.05) than bovine albumin (BSA) at all evaluated pHs. FPH foaming capacity was not affected by pH, however, foam stability was equal or better than that of BSA, especially at pH 4.0 (P ≤ 0.05). These results suggest the possibility of producing FPH with similar or better functional properties than those of functional ingredients, such as SCA and BSA. Furthermore, the data presented support our hypothesis that the high proteolytic activity in Pacific whiting could be used as an advantage in fish protein hydrolysate production or as a processing aid where protein hydrolysis is required.     

Biological value of protein from raw fish and canned fish

The authors evaluated the nutritive value of protein from 4 kinds of raw fish (herring, cod, mackerel, sprat) and its preserves. Experiments were made on rats fed the diets containing fish protein (8-10% of the total diet). Experiments included the determination of apparent and genuine digestibility, net protein utilization, and net dietary protein caloric value. Evidence was obtained that protein from fish and its preserves is characterized by high digestibility coefficient as compared with casein and egg powder. The highest net protein utilization was noted in animal groups fed the diet containing protein from raw fish. Protein assimilability from fish preserves was on the average 15% lower than that from raw fish.     

Comparative study on physicochemical and functional properties of egg powders from Japanese quail and white Leghorn chicken

Physicochemical and functional properties of freeze-dried egg powders (egg white, egg yolk, and whole egg) from Japanese quail and white Leghorn chicken were studied comparatively. All egg powders had protein content in the range of 91.13–97.03 g/100 g powder. The quail egg powder had higher mineral and essential amino acid contents, but lower fat content as compared to chicken egg powders (P < 0.05). Moreover, egg white powder from both quail and chicken presented higher total amino acids content than corresponding whole egg and egg yolk powders, respectively. Fourier transform infrared spectroscopic study revealed that β-sheet is the major secondary structure of all egg powders. Based on differential scanning calorimetry analysis, quail egg powders showed slightly lower denaturation temperatures than corresponding chicken egg powders (P < 0.05). Sodium dodecyl sulfate–polyacrylamide gel electrophoresis study showed the slight difference in protein patterns of corresponding quail and chicken egg powders. The quail egg powders presented higher protein solubility than corresponding chicken egg powders at all pH tested. Furthermore, quail egg powders exhibited higher emulsion activity index and emulsion stability index with higher foam expansion and stability than the corresponding chicken egg powders. Therefore, Japanese quail egg powders could be used as an alternative to white Leghorn chicken egg in the preparation of foods and diets that require high protein content with positive health benefits.     

The Tuna Fishing Industry: A New Outlook on Fish Protein Hydrolysates

Abstract: Tuna (Thunnus spp.) and tuna‐like species are significant sources of food and thus play a very important role in the economy of many countries. More than 48 species of tuna swarm the Atlantic, Indian, and Pacific Oceans, and the Mediterranean Sea. The annual global production of tuna has undergone a marked increase from less than 0.6 million metric tons in 1950 to almost 4.5 million metric tons in 2007. Tuna generally is processed as raw fish flesh and marketed as loins/steaks or as a canned food. In the tuna canning process, only about one‐third of the whole fish is used. Thus, the canning industry generates as much as 70% solid wastes from original fish materials. This waste consists of muscle (after loins are taken), viscera, gills, dark flesh/muscle, head, bone, and skin. Conventionally, these protein‐rich by‐products from the tuna industry are processed into low market value products, such as fish meal and fertilizer. However, a promising alternative use of these by‐products is as functional food ingredients. Fish protein hydrolysate (FPH), which is obtained through hydrolysis of tuna waste, can be used as an ingredient in food industries to provide functional effects such as whipping, gelling, and texturing properties. Recently, FPH was found to be a potential source of antioxidants (such as peptides with anticancer properties), antianemia compounds, and components for use in microbial growth media. This article is intended to summarize the existing knowledge about FPH, highlight some pertinent information related to the tuna fishing industry, and provide a new outlook on the production and applications of FPH.     

Physical Properties of Mixed Dairy Food Proteins

Foods may contain more than one type of protein, and food formulators sometimes combine different proteins for desired synergistic textural benefits. Egg albumin, fish protein isolate, or soy protein isolate were blended with calcium caseinate or whey protein isolate and mixed in water adjusted to pH 2.5, 6.8, and 9.0 at 25 or 60°C. The effect of pH and temperature on solubility, viscosity, and the structure of the resulting gels were determined. The viscosity at the most soluble concentration at 25°C were: egg albumin (175.2 mPa.s/35 wt%), fish protein isolate (2207.4 mPa.s/30 wt%), soy protein isolate (2531.5 mPa.s/10 wt%), calcium caseinate (1115.8 mPa.s/15 wt%), and whey protein isolate (161.2 mPa.s/35%). In mixed protein systems viscosity values were reduced. The values for calcium caseinate or whey protein isolate with egg albumin, at the protein level of 15 g/100 g were: calcium caseinate/egg albumin (10:5 wt%) 535.1 mPa.s and whey protein isolate/egg albumin (10:5 wt%) 8.7 mPa.s. Microscopy imaging revealed changes in protein aggregation clusters during heating of calcium caseinate, egg albumin, and whey protein isolate. Egg albumin acted synergistically to increase viscosity, while fish protein isolate acted antagonistically to reduce viscosity. This knowledge is useful to manufacturers who may seek to enhance food texture by blending different proteins.     

Survival of multidrug-resistant Salmonella typhimurium DT104 in egg powders as affected by water activity and temperature.

A study was done to determine if a four-strain mixture of multidrug-resistant Salmonella typhimurium definitive type 104 (DT104) cells and a four-strain mixture of S. typhimurium non-DT104 cells differed in ability to survive in whole egg powder, whole egg powder supplemented with corn syrup solids (38%) and salt (1.9%), egg yolk powder, and egg white powder as affected by a(w)(0.29-0.37 and 0.51-0.61) during storage at 13 or 37 degrees C for 8 weeks. Rates of inactivation of S. typhimurium DT104 and non-DT104 cells were similar within each set of test parameters. With the exception of whole egg powder supplemented with corn syrup solids and salt, death was enhanced at a(w) 0.29-0.37 compared to a(w) 0.51-0.61 when powders were stored at 13 degrees C. Survival of cells in whole egg powder supplemented with corn syrup solids and salt was significantly (P < or = 0.05) higher compared to survival in other egg powders stored at 13 degrees C. The opposite trend occurred in powders at a(w) 0.5-0.61 stored at 37 degrees C. Survival of S. typhimurium DT104 and non-DT104 cells at initial populations of 5.01-5.39 log10 cfu/g of egg white powder containing 4.9, 6.1, or 8.2% moisture at 54 or 82 degrees C for 7 days or 8 h, respectively, was determined. Rates of inactivation of DT104 and non-DT104 cells did not differ. Both cell types were detected in egg white powder containing 4.9% moisture but not in powder containing 8.2% moisture when held at 54 degrees C for 7 days. Heating at 82 degrees C for 8 h failed to eliminate 5 log10 S. typhimurium per g of egg white powder, regardless of the moisture content.     

Autolysis-assisted production of fish protein hydrolysates with antioxidant properties from Pacific hake (Merluccius productus)

Fish protein hydrolysates (FPH) with antioxidative properties were prepared using Pacific hake fish with high endogenous proteolytic activity from Kudoa paniformis parasitic infection. Infection level of ∼10⁷K. paniformis spores/g fish mince or higher yielded FPH with high antioxidant potential by autolysis and/or Validase^® BNP or Flavourzyme^® 500L. Autolyzing fish mince containing 30 × 10⁶ spores/g for 1 h at 52 °C and pH 5.50 produced FPH (named E-1h) with Trolox equivalent antioxidant capacity (TEAC) in the 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) radical assay of 262 ± 2 μmol/g and oxygen radical absorbing capacity (ORAC) of 225 ± 17 μmol Trolox equivalents/g freeze-dried sample. E-1h FPH also exhibited a marked concentration-dependent scavenging activity on 1,1-diphenyl-2-picrylhydrazyl radical. Antioxidant activity of E-1h FPH was higher (p < 0.05) than BHA and α-tocopherol in a linoleic acid peroxidation system over prolonged storage (∼162 h). Antioxidative FPH from Pacific hake may be useful ingredients in food and nutraceutical applications.     

Optimization of enzymatic hydrolysis of fish soluble concentrate by commercial proteases

Fish protein hydrolysate (FPH) was produced from fish soluble concentrate (FSC), a by-product from canned fish industry, by using Flavourzyme™ and Kojizyme™. Hydrolysis conditions were optimized by using a response surface methodology (RSM). The model equations were proposed with regard to the effects of temperature (T), time (t), and enzyme concentration (E) on the degree of hydrolysis (DH). The optimum values for Flavourzyme™ concentration, substrate concentration, temperature, and hydrolysis time were found to be 50 LAPU/g protein, 20% (w/w), 45 °C, and 6 h, respectively (LAPU; Leucine Aminopeptidase Unit). While those values for Kojizyme™ were 40 LAPU/g protein, 20% (w/w), 50 °C, and 6 h, respectively. Kojizyme™ enhanced the formation of some bitter-taste amino acids such as tryptophan during hydrolysis process whereas Flavourzyme™ did not. The spray-dried FPH produced with Flavourzyme™ contained high protein content (66%). The bitterness of FPH was less than that of 1 ppm caffeine solution.     

ABAM, a model for bioaccumulation of POPs in birds: validation for adult herring gulls and their eggs in Lake Ontario

An Avian BioAccumulation Model (ABAM) of persistent organic pollutant (POP) uptake and elimination in adult life-stage of birds was validated by simulation of concentrations of DDE, dieldrin, mirex, and HCB in herring gull eggs in Lake Ontario for the years 1985, 1990, and 1992. These chemicals represented a range of whole-body half-lives of 82-265 days in the gull. Dietary intake of POPs by a female gull was simulated by a dynamic bioenergetics model which included dependence on temperature, photoperiod, egg production, and feeding chicks. Concentrations in the two main prey fish of the gull in Lake Ontario were used for POP exposure. Clearance from the female was based on a two compartment toxicokinetic model. Egg concentrations were estimated from egg/whole body female concentration ratios. Simulated concentrations were compared to measured concentrations in gull eggs from 4 different colonies in the northern part of Lake Ontario. Simulations using a diet of 81% fish and 19% uncontaminated food resulted in the best fit with least variance among predicted and measured data. The mean ratio of predicted to measured concentrations in eggs was 1.0 +/- 0.27 among chemicals, years, and colonies for this exposure scenario. This result was in excellent agreement with field assessments of herring gull diet composition in Lake Ontario of 80-82% fish. The ability to perform accurate a priorisimulations for the range of test conditions employed in the validation constituted a rigorous test of the soundness of the model's structure and parameterization. With species-specific adjustments, ABAM can be regarded as a general model for lipophilic POPs bioaccumulation in birds.     

Hydrolysis of surimi wastewater for production of transglutaminase by Enterobacter sp. C2361 and Providencia sp. C1112

Surimi wastewater (SWW) is an industrial wastewater, released during the washing step of surimi preparation from minced fish, that causes environmental problem. In this study, SWW produced from ornate threadfin bream (Nemipterus hexodon) was hydrolysed and used to cultivate Enterobacter sp. C2361 and Providencia sp. C1112 for the production of microbial transglutaminase (MTGase, EC 2.3.2.13). The SWW was repeatedly used to wash the fish mince that gained a final protein content of 3.20% (w/v). The commercial protease, Delvolase was the most appropriate protease used to produce fish protein hydrolysate (FPH) from SWW. The FPH at 40% degree of hydrolysis was used instead of a peptone portion in the SPY medium (3.0% starch, 2.0% peptone, 0.2% yeast extract, 0.2% MgSO(4), 0.2% K(2)HPO(4) and 0.2% KH(2)HPO(4), pH 7.0) to cultivate the tested strains at 37°C, shaking speed at 150rpm. Providencia sp. C1112 produced higher MTGase activity (1.78±0.05U/ml) than Streptoverticillium mobaraense (1.61±0.02U/ml) at 18h of cultivation in FPH medium. On the other hand, the Enterobacter sp. C2361 produced lower MTGase activity (1.18±0.03U/ml).     

Effects of spray-dried whole egg and biotin in calf milk replacer

Holstein bull calves (n = 120) were fed milk replacers containing 0, 10, or 20% of the formulation (0, 22, or 44% of crude protein) as spray-dried whole egg powder in a 56-d feeding trial. Milk replacer was medicated with oxytetracycline and neomycin and was fed from d 1 to 42 of the study in a phase-fed program. All experimental milk replacers were supplemented with B vitamins, except biotin. One half of all calves were supplemented with 1 mg/kg of supplemental biotin to determine whether avidin in the egg protein product inhibited growth. Increasing spray-dried whole egg caused a linear reduction in body weight, body weight gain at 28 and 56 d of the study, calf starter intake, and feed efficiency. Calves fed milk replacers containing 0, 10, and 20% spray-dried whole egg gained an average of 486, 369, and 302 g/d, respectively, during the 56-d trial. Efficiency of feed utilization was 446, 318, and 231 g of body weight gain per kilogram of dry matter intake. Improvement in body weight and feed efficiency occurred when calves began consuming calf starter on d 29. Digestibility of protein or fat from egg may have been reduced during the trial; however, the addition of biotin to the milk replacer did not influence animal performance, suggesting that avidin in spray-dried whole egg was not responsible for impaired performance. The spray-dried whole egg product used in this study did not provide nutrients to support adequate growth of milk-fed calves.     

军曹鱼下脚料的脂肪酸组成及其酶解蛋白粉的营养价值研究

利用常规方法分析比较了军曹鱼鱼头、鱼皮、内脏的鱼油脂肪酸组成及其酶解蛋白粉的营养价值.结果表明,军曹鱼鱼头、鱼皮、内脏的粗鱼油和精制鱼油脂肪酸组成主要由C_(14)～C_(22)的17种脂肪酸组成。不饱和脂肪酸含量均为15%左右;二十碳五稀酸(EPA)和二十二碳六稀酸(DHA)总量均为11%左右;鱼头、鱼皮、内脏的酶解蛋白粉的粗蛋白含量(干基)分别为85.46%、90.79%和78.26%,必需氨基酸含量分别为27.67%,34.51%,29.15%.必需氨基酸之间比例适宜。符合FAO/WHO推荐的理想蛋白质模式。     

采用Mixolab 和Rheometer 研究含外源蛋白燕麦面团的热机械学和动态流变学特性

通过酶流变分析仪(Mixolab)和动态流变仪(Pheometer)研究3种不同外源蛋白对燕麦面团体系热机械学和流变学特性的影响。Mixolab 分析结果表明：大豆蛋白和面筋蛋白都使燕麦面团的吸水率增大,蛋清蛋白使吸水率显著下降。3 种蛋白的添加都可显著提高面团形成时间,其中面筋蛋白影响最大,大豆蛋白最小。面筋蛋白和蛋清蛋白都使燕麦面团的稳定时间显著增加,其中含10% 面筋蛋白和15% 蛋清蛋白的燕麦面团具有最好的稳定性。含蛋清蛋白的燕麦面团在淀粉糊化时获得最大的峰值扭矩和回值,且随着其添加量增加而有所增大,大豆蛋白则相反,面筋蛋白对相关参数影响较小。动态流变学实验显示：含面筋蛋白和大豆蛋白的燕麦面团具有较大的弹性模量(G')和黏性模量(G"),且随着添加量的增大而增加,含蛋清蛋白的面团则相反。采用DSC 进一步分析面团的热力学特性显示：蛋清蛋白和大豆蛋白可显著提高燕麦面团的峰值温度和终止温度,并在一定程度上提高面团的热焓值;面筋蛋白则作用不明显。     

Enzymatic hydrolysis of by‐products from the fish‐filleting industry; chemical characterisation and nutritional evaluation

Fish frames without heads from Atlantic cod and Atlantic salmon were proteolysed with the industrial enzymes neutrase®, alcalase® and pepsin for 1, 15, 30, 45, 60, 90 and 120 min. After 120 min of hydrolysis, salmon treated with alcalase and cod treated with pepsin yielded significantly (p < 0.05) higher protein recoveries (67.6 and 64% respectively) as compared to salmon treated with neutrase or pepsin and cod treated with neutrase or alcalase (53–62%). To minimise bitterness in the fish hydrolysates, kojizyme™ was added after 120 min of pre‐hydrolysis with alcalase, and the hydrolysis was run for additional times of 120, 240, 360, 480, 600 and 720 min. Protein recovery did not change significantly during the hydrolysis with kojizyme, but the degree of hydrolysis increased significantly (p < 0.01) in both the cod and salmon hydrolysates. A hydrolysate from cod treated with alcalase (150 min) followed by treatment with kojizyme (510 min) was produced. The final hydrolysate was freeze‐dried to a fish protein hydrolysate (FPH) and chemically characterised. The nutritional value of the FPH was established in an experiment with rats. Inclusion of 10% FPH‐N showed significantly (p < 0.05) higher nutritional value as compared to rats fed higher inclusion levels of FPH. © 2000 Society of Chemical Industry     

鲱鱼蛋白的营养和功能特性

介绍了鲱鱼蛋白质的制备,营养和功能特性,表明了鲱鱼蛋白能作为一种比较好的功能添加剂,营养补充剂和乳化剂。     

Peptides from fish and crustacean by-products hydrolysates stimulate cholecystokinin release in STC-1 cells

Fish protein hydrolysates (FPH) are of significant interest, due to their potential application as a source of bioactive peptides in nutraceutical and pharmaceutical domains. Here, we investigated the action of FPH from blue whiting (Micromesistius poutassou) and brown shrimp (Penaeus aztecus) on cholecystokinin release from intestinal endocrine cells (STC-1). We demonstrated for the first time that FPH were able to highly stimulate CCK-releasing activity from STC-1 cells and that this stimulation was mainly due to peptide molecules. The partial purification of CCK-stimulating peptides showed that their apparent molecular weight ranged between 1000 and 1500 Da for fish and crustacean FPH, respectively. Finally, in an aim to industrially produce hydrolysates enriched in CCK-stimulating molecules, we tested the effects of membrane processes (ultrafiltration and nanofiltration) on active peptide enrichments.