The role of edible bird's nest and mechanism of averting lead acetate toxicity effect on rat uterus

Aim

This study aimed to evaluate the protective effect of edible bird's nest (EBN) supplement on the uteri of rats exposed to lead acetate (LA) toxicity.

Materials and Methods

Five treatment groups were established as follows: Group 1 (C), which was given distilled water; Group 2 (T0), which was administered with LA (10 mg/kg body weight [BW]); and Groups 3 (T1), 4 (T2), and 5 (T3), which were given LA (10 mg/kg BW) plus graded concentrations of 30, 60, and 120 mg/kg BW of EBN, respectively. Rats were euthanized at week 5 to collect blood for superoxide dismutase (SOD) assay, and uterus for histomorphological study and expression analyses of epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), and proliferating cell nuclear antigen (PCNA).

Results

Results revealed that LA causes destruction of uterine lining cells and necrosis of uterine glands of exposed rats without EBN supplement while the degree of damage decreased among EBN treated groups; T3 showed the highest ameliorating effect against LA toxicity, as well as an increased number of uterine glands. Increased levels of SOD were also achieved in EBN supplemented groups than the controls. Results of immunohistochemistry showed significantly higher expressions of EGF, VEGF, and PCNA levels (p<0.05) in T3 compared to other treatments. EBN maintained upregulation of antioxidant - reactive oxygen species balance.

Conclusion

The findings showed that EBN could ameliorate the detrimental effects of LA toxicity on the uterus possibly by enhancing enzymatic antioxidant (SOD) activity as well as expressions of EGF, VEGF, and PCNA with cell proliferation roles.

Effects of EBN on embryo implantation, plasma concentrations of reproductive hormones, and uterine expressions of genes of PCNA, steroids, growth factors and their receptors in rats

This study was conducted to determine the effect of edible bird's nest (EBN) supplement on uterine function and embryo-implantation rate. A total of 24 adult female rats, divided equally into four groups, were treated with different doses of EBN for 8 weeks. In the last week of treatment, intact fertile male rats were introduced into each group (three per group) for overnight for mating. On day 7 post-mating (post-implantation), blood samples were collected from the hearts of anaesthetised rats that were later sacrificed. The uteri were removed for assessment of embryo implantation rate, histological and electron microscopic examination, and immunohistochemical analyses. Results showed that as the concentration of EBN supplemented increased, the pregnancy and embryo implantation rates were also increased in the treated groups; significantly at G3 and G4. Although histological evaluation did not show much difference among the groups, scanning electron microscopic examination showed enhanced development of elongated microvilli and pinopods in G4. Results also revealed up-regulated expressions of epidermal growth factor (EGF), EGF receptor (EGFR), vascular endothelial growth factor (VEGF), proliferating cell nulear antigen (PCNA), and progesterone and estrogen receptors (P₄R, E₂R) in the uteri of treated groups. Moreover, plasma E₂, P₄, growth hormone (GH) and prolactin (P) levels were higher (p < 0.05) in G3 and G4. The EBN increased the antioxidant (AO) and total AO capacities (TAC) and reduced oxidative stress (OS) levels in pregnant rats. In conclusion, findings of this study revealed that EBN enhances fertility and embryo implantation rate via promoting proliferation and differentiation of uterine structures as evidenced by the upregulation of the expressions of steroid receptors, EGF, EGFR, VEGF, and PCNA in the uterus. Furthermore, observations of improved growth of ultrastructural pinopods that assist in embryo attachment with uterine epithelium, increased concentrations of E₂, P₄, GH and P levels, as well as increased AO capacities with reduced OS levels in the treated groups might reflect additional possible mechanisms by which EBN enhances embryo implantation rate and pregnancy success.

Effect of different pretreatments on functional properties of African catfish (Clarias gariepinus) skin gelatin

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.

A review of fish-derived antioxidant and antimicrobial peptides: their production, assessment, and applications

Fishes are rich sources of structurally diverse bioactive compounds. In recent years, much attention has been paid to the existence of peptides with biological activities and proteins derived from foods that might have beneficial effects for humans. Antioxidant and antimicrobial peptides isolated from fish sources may be used as functional ingredients in food formulations to promote consumer health and improve the shelf life of food products. This paper presents an overview of the antioxidant and antimicrobial peptides derived from various fishes. In addition, we discuss the extraction of fish proteins, enzymatic production, and the techniques used to isolate and characterize these compounds. Furthermore, we review the methods used to assay the bioactivities and their applications in food and nutraceuticals.

Effect of retorting and oven cooking on the nutritional properties of beef frankfurters blended with palm oils

The effect of retorting and oven cooking on the nutritional properties of beef frankfurters blended with palm oil (PO), red PO35 and red PO48 were compared against the control beef fat treatment. Red PO oven-cooked beef frankfurters resulted in a significant loss of vitamin E from 538.5 to 287.5 microg after 6 months. Oven cooked sausages stored at -18 degrees C and retorted sausages stored for the 6 months of shelf studies resulted in more than 90% loss of alpha-carotene and beta-carotene in red PO beef frankfurters. Cholesterol was reduced at the range of 29.0-32.2 mg/100 g when beef fat was substituted with palm-based oils, in beef frankfurters. Differences of heat treatments did not significantly change THE cholesterol content, within all treatments. This study showed the potential of utilizing red palm oils as animal fat analogues in improving vitamin E, reducing cholesterol but not carotenes in beef frankfurters.

Protein quality of anchovy, mackerel and canned sardine samples

The protein nutritive value of anchovy, mackerel and canned sardine samples together with casein as a reference formulation were evaluated. Proximate composition, protein quality and protein digestibility were determined. Procedures for evaluation included Protein Efficiency Ratio (PER) using the rat bioassay and in vivo Apparent Digestibility (AD). Rats fed with canned sardine diet had the highest mean body weight (154.8±12.28g) while rats fed with anchovy diet had the lowest mean body weight (145.27±15.89g) with significant differences between all the groups. Mean body weight of rats fed with selected fish diet was higher compared to rats fed with casein diet. For PER value, canned sardine has the highest value (2.48), followed by anchovy (2.46) and mackerel (2.34). PER value for all selected fish is lower than that for casein (3.14). Mackerel had the highest value of in vivo AD (96.99%), followed by casein (96.96%), canned sardine (96.88%) and anchovy (91.29%). In conclusion, among the types of fish compared, sardine had the highest protein quality while mackerel showed the highest digestibility.

Chemical, physical and sensory properties of chicken frankfurters substituted with palm fats

Physico-chemical and sensory characteristics of frankfurters prepared with three types of palm fats (PF60: 40, PF70: 30 and PF80: 20) and palm olein (POo) at 20 and 25% of fat levels were studied. Incorporation of different fats at 20 and 25% did not affect the cooking yields of the frankfurters. Frankfurters incorporated with 25% POo showed the highest value of water-holding capacity (WHC) among eight formulations. The frankfurters containing POo showed the least cooking loss compared to those with palm fats. The incorporation of different type and level of fats resulted in significant changes in the colour (lightness, redness, yellowness) of frankfurters. Texture profiles of both raw and cooked frankfurters were found to be altered by the blending of different type and level of fats. In raw frankfurters, hardness for frankfurters mixed with palm fats were significantly higher than the one with POo but greater values for cohesiveness was observed in raw frankfurters blended with POo. Lowest chewiness was demonstrated by frankfurters mixed with 20% POo. Grilling increased the hardness values of all frankfurters. Contrary to the raw counterparts, cooked frankfurter with POo was the hardest among all formulations. Cohesiveness and chewiness was also found to be significantly higher for cooked frankfurters mixed with POo. Raw frankfurters with fat content of 25% showed greater value in hardness than those of 20%. However, there were no significant differences (P > 0.05) observed for all the texture profile attributes in cooked frankfurters due to fat levels. In sensory evaluation, frankfurters prepared with POo were found to be most acceptable by consumer panels as they scored the highest for hardness rating, chicken flavour, oiliness and overall acceptance attributes.

Quality of mechanically deboned chicken meat frankfurter incorporated with chicken skin

Four formulations were processed into frankfurters with different ratios of mechanically deboned chicken meat (MDCM) and cooked chicken skin (CCS) i.e. 80/0, 70/10, 60/20 and 50/30. The products were evaluated for proximate composition, cholesterol content, colour; 'L' value (lightness) and 'a' value (redness), percentage of cooking loss, physical measurements (shearforce-kgf and folding test), thiobarbituric acid value (TBA) and taste panel evaluation. The increment of CCS in the frankfurters increased the contents of moisture, ash, protein, fat, cholesterol, the lightness ('L' value) and redness ('a' value). After 3 months of frozen storage, the increment continued except for the moisture contents for formulations with 20 and 30% CCS. The lipid oxidation (TBA value) and cooking loss were lowered in formulations with CCS. After 3 months of frozen storage, TBA value decreased, while the cooking loss increased for all the formulations. The addition of CCS increased hardness of the frankfurters but affected folding ability, with formulation with 10% CCS scoring better grade. Sensory evaluation was carried out using 30 untrained panelists to evaluate aroma, colour, appearance, hardness, juiciness, chicken taste, oily taste, rancid taste and overall acceptance of the products. The addition of CCS in the frankfurters at 10 and 20% resulted in products with taste and texture that were acceptable after 3 months of frozen storage.

Replacement of animal fat with fractionated and partially hydrogenated palm oil in beef burgers

Four formulations of burgers, prepared with 65% lean meat and 15% fat consisting of RBD palm stearin (PS), Socfat 4000P and Socfat 4100P and beef fat (BF) as control were evaluated for solid fat content (SFC), slip melting point (SMP), cooking loss, proximate analysis (moisture, fat and protein), colour, i.e. lightness ('L'), redness ('a') and yellowness ('b'), free fatty acid (FFA), iodine value (IV), thiobarbituric acid (TBA) and texture profile analysis (TPA). Sensory evaluation was carried out for texture, juiciness, aroma, oiliness and overall acceptance. SFC and SMP for raw and cooked SF4000P beef burgers were closest to BF control burgers, falling into the range of 35-40 degrees C. Cooking loss was highest for PS burgers, there were no significant differences (P > 0.05) amongst BF, SF4000P and SF4100P burgers. Proximate analysis on raw burgers showed SF4000P to contain high fat and lowest moisture contents. Objective textural measurements using texture profile analysis (TPA) for all cooked burgers showed no significant differences (P > 0.05) for springiness and cohesiveness. Variation of values among the formulations for hardness, gumminess and chewiness are explained by the differences of SFC for beef burgers with various types of fats. Raw and cooked PS burgers have the lightest 'L' values compared with other fat-substituted burgers while BF, SF4000P and SF4100P indicated no significant differences (P > 0.05) for 'L', 'a' and 'b' values. Beef fat showed the highest amount of free fatty acids (FFA) compared to palm oil samples. For the iodine value (IV), SF4000P showed the highest value which means that it contained the highest level of unsaturated fatty acids followed by PS, BF and SF4100P successively. SF4000P had the highest TBA values followed successively by BF, PS and SF4100P. For sensory evaluation, PS burgers had the least oily taste. This may be due to its high cooking loss. Taste panelists could not differentiate burgers with substituted vegetable fats against the control burgers.

Effect of non-meat proteins, soy protein isolate and sodium caseinate, on the textural properties of chicken bologna

Nine formulations were processed into bologna with different ratios of soy protein isolate (SPI):sodium caseinate (SCA), i.e. 1:1, 1:2.5, 1:5, 5:1, 5:2.5, 5:5, 10:1, 10:2.5 and 10:5. The products were evaluated for yields, emulsion stability, physical measurements (shearforce-kgf and folding test) and taste panel evaluation. Formulations with 5:1 and 5:5 SPI:SCA had lower liquid loss resulting in higher yields while the others had poor emulsion stability and high liquid loss. Firmer texture was exhibited by formulations 1:1, 5:1 and 10:1 SPI:SCA but formulation with 1:1 SPI:SCA showed better gelation followed by 1:2.5, 1:5, 5:1, and 5:2.5. The other formulations had poor gelation and binding properties, especially formulation with 10:5 SPI:SCA. Sensory evaluation was carried out using 30 untrained panelists. Attributes evaluated were aroma, texture, chewiness, juiciness, saltiness, chicken taste and overall acceptance. Formulation with 5:1 SPI:SCA was more acceptable for texture, chicken taste and overall acceptance while formulation with 1:1 SPI:SCA was more acceptable for the chewiness, juiciness and saltiness attributes. There was no significant difference (P > 0.05) in aroma attribute, for all formulations.

The nutritional value of some processed meat products in Malaysia

Per capita consumption of meat and meat products in Malaysia more than doubled from 15.70 kg in 1970 to 35.71 kg in 1990. This increase in meat consumption is mainly due to the rapid development and wide acceptance of value added meat and poultry products amongst Malaysian consumers. Meat products such as burgers, sausages, hotdogs and nuggets are widely accepted and consumed by all ethnic groups at home as well as in the fast food restaurants. The significant expansion of the fast food industry and the increase consumption of processed meat products makes it necessary for a re-evaluation of the nutritional quality of popular meat products currently available in the market. This review paper described the quality of some processed meat products, their proximate composition, meat quality, use of non meat proteins and binders, and the use of additives in the formulation of burgers, frankfurters, nuggets, bologna, chicken and beef balls. Preliminary results on the protein efficiency ratio of local meat products seemed favourable but this study is limited to only one laboratory. In vivo and in vitro protein digestibility studies indicated high values on the digestibility of locally manufactured meat products. Proximate analysis of the raw materials used in the formulation of such products showed many with high fat and low protein contents being utilized. The meat content was lower than the minimum amount stated by the food regulation. This paper concludes that due to lack of information and studies on the nutritional composition of processed meat products, concerned bodies should take positive steps to generate reliable data to elucidate the actual nutritional composition of such products. It is also observed that many by-products from the animal industry from non-conventional sources are increasingly being utilized in the manufacture of processed meat product.