The purpose of this study was to investigate the effect of papaya leaves crude extract on the physicochemical properties of marinated chicken meat. Papaya leaves was extracted with sodium acetate (CH3COONa) buffer (pH 7.2) at room temperature. Protein concentration and activity of enzyme in the crude extract were determined by using UV-Spectrophotometer. The crude extract was mixed with marinated ingredients and then coated onto chicken meat which was subsequently kept for overnight in refrigerator at chill temperature. Protein concentration of the enzyme was identified as 166.36 μg/μl and enzyme activity was 1.28 CDU/ml. Results also showed that lightness (L*), cooking loss and shrinkage of the marinated chicken were higher than control. Redness (a*), yellowness (b*), protein content, water-holding capacity, shear force, and texture profile analysis were lower than control. Microstructure analysis showed that the chicken meat muscle was destructed in the presence of papaya crude extract. Sensory acceptability evaluation of marinated chicken which was carried out by using 9 point hedonic scale suggested that chicken meat treated with papaya crude extract gave significant effect on texture, juiciness, flavour and overall acceptability compared to commercial bromelain. Additionally, the use of papaya crude extract gave a significant effect on the physicochemical properties of marinated chicken.
This study was carried out to extract, partially
purify and characterise protease from guava peel. The
extracted protease was purified using 60% ammonium sulfate
precipitation method followed by gel filtration
chromatography. The obtained proteases were analysed for
protein concentration, proteolytic activity, total proteolytic
activity, specific activity, percent recovery, purification fold,
molecular weight distribution, optimum temperature and pH.
Guava peel contains 7.10% protein. The optimum temperature and pH of the protease was achieved within the range of 40 to
60°C and pH 4 to 6, respectively, where maximum activity
identified was 50°C and pH 5. Total activity decreased with the
purification steps involving 60% ammonium sulfate
precipitation and dialysis but subsequently increased after
being subjected to gel filtration chromatography. This study
suggested that further purification using gel filtration
chromatography increases the proteolytic activity of guava peel
protease.
One of the main obstacles of protein hydrolysate application in food is bitterness and fishy off-flavor. Pretreatment
of the raw materials prior to hydrolysate production is one way of preventing the development
of this undesirable flavor. In this study, silver catfish which was used as the raw material was soaked in
lime or tamarind juice prior to hydrolysis process to produce hydrolysate with reduce bitterness and fishy
off-flavor. Initially, the fish flesh was pre-treated by soaking in either water, lime juice (Citrus
aurantifolia) or tamarind juice (Tamarindus indica). After the pre-treatment, the homogenised flesh was
hydrolysed in Flavourzyme 500L at pH 7, 50°C and enzyme substrate ratio (ES) of 2% for 120 minutes to
produce control (CH), lime (LIH) and tamarind (TAH) hydrolysates after soaking in water, lime juice and
tamarind juice, respectively. The physicochemical and sensory properties of the hydrolysates were
compared. Soaking in tamarind juice resulted in significantly (p0.05) in yield. TAH was
significantly (p
Protease was extracted from the viscera of torpedo scad fish (Megalspis cordyla) to obtain the crude extract which was then partially purified in 70% ammonium sulphate. The collected precipitate was dialysed and subsequently immobilized in sodium alginate and calcium chloride solution. The optimum concentrations of sodium alginate and calcium chloride to produce the highest yield of immobilized protease was determined by using Response Surface Methodology (RSM). From the results, the optimum conditions obtained were 2.5% of sodium alginate and 0.25 M of calcium chloride achieving a yield of 55.52%. Thus, the utilization of 2.5% sodium alginate and 0.25 M calcium chloride as the immobilization media were able to produce yield of immobilized protease from torpedo scad viscera with the highest proteolytic activity.
Protease is the enzyme which can be extracted from plant, animal, and microorganism. About 60% enzymes widely used nowadays are proteases. The objectives of this study were to determine the proteolytic activity and molecular weight distribution of protease extracted from Pangasius sutchi silver catfish viscera. Crude protease was extracted in 10 mM Tris-HCL buffer at pH 8.0. Subsequently, the protease was partially purified in stages beginning from ammonium sulphate precipitation (60%) followed by dialysis and gel filtration chromatography. Fractions collected from gel filtration chromatography was freeze-dried and analysed for optimum temperature and pH. Results showed that the viscera contain 13.79% protein. The protease total activity was 344.08 U with specific activity of 31.92 U/mg, purification fold 3.5 and 63.16% percent recovery. The protease proteolytic activity was optimum at 60 °C and pH 6. This study indicated that purification steps involving ammonium sulphate precipitation at 60% saturation, gel filtration chromatography and freeze drying led to the production of Pangasius sutchi visceral protease with a relatively high proteolytic activity.
Protease was extracted from two maturity stages of noni fruits (Morinda citrifolia L.), unripe (stage 1) and ripe (stage 5). The crude extract was partially purified by acetone precipitation method followed by dialysis, gel filtration chromatography and freeze drying. Protein concentrations, proteolytic activity, molecular weight distribution, pH stability, temperature stability and storage efficiency of the resulting protease were evaluated. The unripe and ripe noni fruit contains 0.65 and 0.35% protein, respectively. Molecular weight of the proteases from both stages ranged approximately between 3 to 28 kDa based on the SDS-PAGE results. The optimum activity were at pH 7s and 6, temperatures of 40 and 50°C, respectively for proteases obtained from the unripe and ripe fruit. Analysis from the freeze dried protease indicated that protease from ripe noni fruits had higher protein concentration and specific activity compared to those from unripe fruit. However, it is more sensitive to pH and temperature and less stable during storage as it shows lower proteolytic activity compared to protease from unripe fruit. Based on its high proteolytic activity reaching up to 70.31 U/mg and storage stability (30% lost of activity), noni fruit could be an alternative source of plant protease.
Proteases were extracted from starfruit at maturity Index 2 (unripe, light green) and Index 7 (very ripe, orange) and partially purified using acetone and 40% ammonium sulfate precipitations. Higher yield and proteolytic activity were observed for proteases purified using acetone than 40% ammonium sulfate. As for maturity index, yield and protein concentration of proteases from Index 2 were higher than those from Index 7. SDS-PAGE result showed intense bands for acetone proteases while a distinct band at 50 kDa was observed in all the proteases. Enzyme activity decreased during the seven days storage at 4°C with minimum relative activity of 70% achieved for acetone proteases at day seven. This study suggested that acetone precipitation is more effective method for purifying starfruit protease based on the yield and proteolytic activity compared to using 40% ammonium sulphate precipitation. In order to obtain higher protein concentration and proteolytic activity, starfruit at the unripe stage, Index 2 is a better raw material than Index 7 to be used for protease production.
Threadfin bream (Nemipterus japonicus) skin gelatin was enzymatically extracted for 6 or 12 hrs at 60°C, pH 8 in the presence of alcalase. The gelatin was analyzed for yield, gel strength, melting point, setting point, setting time, viscosity, solubility and molecular weight distribution. The gelatin was also compared with commercial gelatin. The 12 hrs extraction time yield 7.74% gelatin and the gelatin was more soluble while 6 hrs gelatin resulted in 5.69% yield. Gel strength of the extracted gelatin decrease with longer extraction time. The 6 hrs gelatin exhibited gel strength of 324.93g which was very close to the commercial gelatin (342.10g) while 12 hrs gelatin gel strength was 202.47g. Melting points of threadfin bream gelatin increased when the extraction time increased ranging from 25.53 to 29.42°C while commercial gelatin melted at 34.03°C. Threadfin bream gelatins set at lower temperature and longer time with increase in extraction time compared to commercial gelatin. The gelatin extracted for 6 hrs resulted in higher gel strength, viscosity, melting point, setting point and shorter setting time than the 12 hrs gelatin. This shows that the 6 hrs extracted gelatin is more suitable to be used in food production than the 12 hrs gelatin.
Collagen was extracted from catfish (Clarias gariepnus) waste using 0.5M acetic acid and its subsequent precipitation in 2.6M NaCl. The resultant collagen was analysed with respect to its moisture content and physicochemical properties including yield, pH, protein content, colour, odour and thermal stability. A yield of 16.4% and positive collagen attributes indicate that catfish waste has potential as a collagen source. The snowy white, crystal-like and light textured collagen comprises of 5.97% protein and 0.46% moisture, and exhibits a pH of 4.75. Sensory evaluation indicates that the collagen has a slight fishy odour. Viscosity analysis indicates a steady decrease with increasing temperature over the range considered (20-50°C). The pale colour exhibited and limited odour emitted by the extracted collagen indicate that catfish waste collagen could be applied in the food industry without resulting in any undesirable food products attributes. Differential Scanning Calorimetry (DSC) analysis indicated that the collagen exhibits good thermal stability and denatures at a high temperature in a similar manner to mammalian collagen.
Silver catfish (Pangasius sutchi) skin gelatin was extracted to determine the effects of extraction time on the functional properties of the gelatin in terms of solubility, protein solubility as a function of pH and sodium chloride concentration, emulsifying capacity and stability, water holding capacity, fat binding capacities and foaming properties. Silver catfish skins were washed in sodium chloride (NaCl) solution prior to pre-treatment in sodium hydroxide (NaOH) and acetic acid solution. Gelatin was extracted at 50ºC for 6, 8, 10 and 12 hours extraction time followed by freeze drying. The extraction of silver catfish skin gelatin at 50 ºC for 12 hours was more effective than extraction at 6, 8 and 10 hours where the gelatin was characterized by higher emulsifying capacity (52.63%), emulsifying stability (47.83%), water holding capacity (31.78 mL/g), fat binding capacities (54.76%), foaming capacity (41.47 mL) and foaming stability (56.42%) than gelatins extracted at other extraction time. The longer the extraction time, the better the functional properties of the gelatin. Based on its good functional properties, silver catfish skin gelatin may be useful in various food applications such as soups, sauces and gravies.
Unripe and ripe bilimbi (Averrhoa bilimbi. L) were ground and the extracted juices were partially purified by ammonium sulfate precipitation at the concentrations of 40 and 60% (w/v). The collected proteases were analysed for pH, temperature stability, storage stability, molecular weight distribution, protein concentration and protein content. Protein content of bilimbi fruit was 0.89 g. Protease activity of both the unripe and ripe fruit were optimum at pH 4 and 40ºC when the juice were purified at 40 and 60% ammonium sulfate precipitation. A decreased in protease activity was observed during the seven days of storage at 4°C. Molecular weight distribution indicated that the proteases protein bands fall between 10 to 220 kDa. Protein bands were observed at 25, 50 and 160 kDa in both the unripe and ripe bilimbi proteases purified with 40% ammonium sulfate, however, the bands were more intense in those from unripe bilimbi. No protein bands were seen in proteases purified with 60% ammonium sulfate. Protein concentration was higher for proteases extracted with 40% ammonium sulfate at both ripening stages. Thus, purification using 40% ammonium sulfate precipitation could be a successful method to partially purify proteases from bilimbi especially from the unripe stage.
This study was carried out to determine the antioxidant activity of threadfin bream (Nemipterus japonicas) hydrolysate (TFBH) in comparison with the commercial antioxidants; α-tocopherol and LYK Nanox 189 and to evaluate the oxidative stability of chicken balls added with 20% TFBH during the 15 days storage at 4ᵒC. TFBH was prepared by hydrolysis with Alcalase at pH 8.5, 60ᵒC, enzyme /substrate ratio of 2% for 2 hours. The results showed some antioxidant activities of the hydrolysate even though the activity was lower than the commercial antioxidants. This was based on the ferric reducing antioxidant power (FRAP) analysis and 2, 2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity. Based on the induction time measured by Rancimat, TFBH when added into the chicken balls was capable of delaying the oxidation process during the 15 days storage at 4ᵒC. The observation was also supported by peroxide and TBARS values. Therefore, TFBH can be used in food to delay the oxidation process during storage
In this study, Hydrolysate from angelwing clam (Pholas orientalis) was produced at 0, 1, 2 and 3 hrs and E/S ratio of 0.5 and 3% using alcalase where the pH and temperature were kept constant at pH 8.5 and 60°C, respectively. The hydrolysates were analysed for antioxidant and functional properties such as solubility, emulsifying properties and water and oil holding capacity. Degree of hydrolysis (DH), yield, functional and antioxidant properties were influenced by the hydrolysis time and E/S ratio. Higher enzyme concentration (E/S 3%) and longer hydrolysis time increased the DH. Yield was higher at E/S 3% but reduced with hydrolysis time. Longer hydrolysis time produced more soluble hydrolysate and higher metal chelating activity but lower in emulsifying properties and DPPH activity. Higher enzyme concentration resulted in increase only in solubility and metal chelating activity. This study revealed that enzymatic hydrolysis using alcalase should be performed at shorter hydrolysis time using intermediate concentration of enzyme (E/S between 0.5 to 3%) in order to produce angelwing clam hydrolysate with collectively good functional and antioxidant properties
This study was conducted to evaluate the effect of pre-treatment on the fishy flavour and odour removal of gelatine extracted from the skin of sutchi catfish (Pangasius sutchi). Pre-treatment of the skin involved soaking at 4°C in distilled water (GC), lime followed by tamarind (GLT) or salt followed by activated carbon (GSC) prior to extraction in warm distilled water (50°C) for 12 hours. Yield, physical properties and sensory were determined. Results showed that GLT produced highest yield (19.72%) compared to GSC (15.01%) and GC (15.81%). Although, GLT exhibited lowest gel strength (282.29g), viscoelasticity (14.1ºC) and setting point (10.46ºC) compared to other pre-treatments, fishy flavour and odour of the gelatine were almost absent with the score of 1.68 and 1.74, respectively. These values were below those of reference which are 1.87 (fishy flavour) and 2.71 (fishy odour) denoting from ‘absent to weak’. Since fishy flavour and odour were almost absent, soaking sutchi catfish skin in lime followed by tamarind could be a good method for achieving the desired sensory attributes of the freshwater fish by the reduction of the gelatine off flavour.