Protein Efficiency Ratio (PER) is the most widely used method for determining protein quality. The studies involved a few category of products as raw materials namely poultry products, beef burger products, fish and fish products, soy products and palm kernel cake in animal diet preparation were compiled to compare the data. Data from the proximate analysis showed that protein content in soy protein isolate (SPI) was the highest (95.00%) followed by meat such as mackerel fish (89.09%) and beef (88.60%). Results from feed consumption and total protein consumed showed that the rats fed with mechanically deboned poultry meat (MDPM) products (excluding broiler back) consumed more feed, ranging from 469.2g to 422.3g during the study while the lowest total feed consumed (157.7g) was recorded in the rat fed a diet of fermented palm kernel cake (fPKC). The total protein consumed by rat for diets of fish and fish products such as canned sardine was 62.36g, mackerel 61.76g and anchovy at 58.91g, followed by MDPM products. Tempeh (14.72g) and fPKC diet (16.3g) were among the lowest total protein consumed by the rats. Growth and PER data for rats fed a diet of canned sardine, anchovy and mackerel, as well as mechanically deboned turkey meat (MDTM) and mechanically deboned chicken meat (MDCM) had higher mean body weight (154.80g, 145.20g, 144.81g, 148.7g and 142.5g respectively) compared to rats fed with plant protein diet such as SPI, tempeh and PKC (34.79g, 16.34g and 16.60g respectively) whereas rats fed diets containing fPKC had a mean body weight loss of 24.4g. MDPM showed higher PER value (ranging from 3.01 to 3.34) compared to hamburger group, pure beef and fish group. Tempeh and SPI had lower PER of 1.02 and 1.52 respectively while the lowest PER of 0.50 and -1.50 were shown in PKC and fPKC. The highest digestibility was shown in mackerel (96.99%), followed by canned sardine (96.88%), tempeh (91.41%), meat (90.79%) and pure beef burger (90.04%) while digestibility of PKC and fPKC were much lower (45.70% and 22.60%). Lipid profile of rats fed with palm based fat beef burger showed that palm fat(PF) and red PF did not affect the total cholestrol concentration but resulted in higher high density lipoprotein (HDL)- cholesterol concentration in their blood serum. In summary, the utilization of PF and red PF in beef burger increased the HDL-cholesterol and has no effect on the concentration of total cholesterol in rat blood serum.
Research and development trends will continue to design innovative composite foods in which muscle proteins are combined with non-conventional animal products, non-meat proteins and functional food additives, many of which have lost their original inherent properties and characteristics. Composite food are products with meat, non-meat proteins, fats, carbohydrates and functional ingredients such as pre-emulsion, probiotics, enzymes, bioactives, peptides, hormones, emulsifiers, gelatin, animal fats/oils, alcohol and visceral tissues. Traceability of halal meat raw materials should start at the point of animal breeding, production to the stage of halal slaughter, processing operations and final point of consumption. Traceability of food additives used in the food industry remains a major hurdle for the Muslim community seeking halal food. The processes and technological advancements made in raw material processing, ingredient extractions, modifications, purification and resynthesized into many food ingredients make the question of traceability and solving of the materials and processes that are halal a monumental task. Food is only halal if the entire food chain from farm to table, is processed, handled and stored in accordance with the syariah and/or halal standards or guidelines, such as in the Jabatan Kemajuan Islam Malaysia (JAKIM): General guidelines, Malaysia Standards MS 1500:2009 and Codex Alimentarius (Food Labeling). Here lies the challenge and importance of traceability to verify the ‘wholesomeness’ of the sources of halal raw materials and final meat-based food products.
Cronobacter sakazakii is an emerging food borne pathogen which has been associated with outbreaks of a rare form of infant meningitis. Although the origin of the microorganism has not been established, several
infection cases have been associated with the consumption of contaminated powdered infant formula (PIF). In the present study, growth characteristics of three C. sakazakii strains isolated from PIF samples and C.
muytjensii strain ATCC 51329, which was formerly the ATCC Preceptrol™ strain for the quality control of
‘Enterobacter sakazakii’ prior to the taxonomic revision, were investigated in Tryptone Soya broth (TSB) and
reconstituted PIF at 4, 10, 25, 37, 45 and 50ºC. The viability of heat treated cells of Cronobacter strains was
evaluated by plating on Violet Red Bile Glucose agar (VRBGA) and the Druggan-Forsythe-Iversen (DFI)
chromogenic agar followed by incubation at 37ºC. These strains were also subjected to higher temperatures
between 52 to 60ºC to measure their thermal tolerance. The mean generation time of all Cronobacter strains
were slightly lower in PIF than in TSB. C. muytjensii ATCC 51329 showed lower generation time in all culture
media and all temperatures compared to the Cronobacter food isolates, but the results were not significantly
different (P>0.05). The results also indicated that combination of PIF: DFI culture media had higher recovery at
all temperatures compared to other combinations. Survival study also indicated that C. muytjensii ATCC 51329
had higher D-value compared to food isolates at all incubation temperatures.
Pretreatments with different types of alkali and acid were compared to determine their effects on gelatin extraction from African catfish (Clarias gariepinus) skin. The study was divided into three parts. In the first part, the skins were only treated with alkaline (Ca(OH)2 or NaOH) solution or pretreated with acetic acid solution. For second part, combination of alkali and acid pretreatment was carried out. For the third part, the skins were first treated with NaOH solution, followed by the treatment with acetic acid, citric acid or sulfuric acid solution. Functional properties including the yield of protein recovery, gel strength, viscosity, pH and viscoelastic properties were determined on gelatins obtained with different pretreatment conditions. Pretreatment with alkali removed noncollagenous proteins effectively, whilst acid pretreatment induced some loss of collagenous proteins. Combination of alkali and acid pretreatment not only removed the noncollagenous proteins and caused a significant amount of swelling, but also provided the proper pH condition for extraction, during which some cross-linkages could be further destroyed but with less breakage of intramolecular peptide chains. Pretreatment of catfish skins with 0.2 N NaOH followed by 0.05 M acetic acid improved yield of protein recovery, gel strength, viscosity, melting temperature and gelling temperature of gelatin extract.
Skin and bone gelatins of pangasius catfish (Pangasius sutchi) were hydrolyzed with alcalase to isolate Angiotensin Converting Enzyme (ACE) inhibitory peptides. Samples with the highest degree of hydrolysis (DH) were separated into different fractions with molecular weight cut-off (MWCO) sizes of 10, 3 and 1 kDa, respectively and assayed for ACE inhibitory activity. Skin and bone gelatins had highest DH of 64.87 and 68.48 % after 2 and 1 h incubation, respectively. Results from this study indicated that by decreasing the molecular weight of fractions, ACE inhibitory activity was increased. Therefore, F3 permeates (MWCO
Edible bird's nest (EBN) is widely consumed as a delicacy and traditional medicine amongst the Chinese. In the present study, for the first time, the antioxidant properties of an EBN pepsin-trypsin hydrolysate of the swiftlet species Aerodramus fuciphagus and its ultrafiltration fractions were investigated. Thirteen peptides with molecular weights between 514.29 and 954.52 Da were identified in the EBN fraction with the use of mass spectrometry. Two novel pentapeptides Pro-Phe-His-Pro-Tyr and Leu-Leu-Gly-Asp-Pro, corresponding to f134-138 and f164-168 of cytochrome b of A. fuciphagus, indicated the highest ORAC values of 14.95 and 14.32 μM of TE μM(-1) peptide, respectively. Both purified peptides showed resistance against simulated gastrointestinal proteases. In addition, both peptides had no in vitro cytotoxicity on human lung MRC-5 cells and prevented human liver carcinoma HepG2 cellular damage caused by hydroxyl radicals. Therefore, it is suggested that EBN protein hydrolysates are a good source of natural antioxidants and could be applied as nutraceutical compounds.
This study was conducted to evaluate the kinetic characteristics of proteolytic activity of proteases on Channa striatus protein fractions. Degree of hydrolysis (DH), amino acid composition and kinetic parameters of sarcoplasmic and myofibrillar proteins were investigated when incubated with proteinase K and thermolysin, separately. After 30 min incubation with proteases, a decrease in DH of sarcoplasmic protein was observed whereas, hydrolysis of myofibrillar protein with proteases took 2 h with an increase in DH. The major amino acids were glutamic acid (16.6%) in thermolysin- myofibrillar hydrolysate followed by aspartic acid (11.1%) in sarcoplasmic protein fraction with no enzyme treatment and lysine (10%) in thermolysin-myofibrillar hydrolysate. The apparent Michaelis constant of proteinase K was lower than thermolysin for both sarcoplasmic and myofibrillar proteins. However, rate of turnover and enzyme efficiency suggested that sarcoplasmic and myofibrillar proteins are suitable substrates for proteinase K and thermolysin hydrolytic reaction, respectively.