Chicken fat is a potential bioresource that can be developed into a commercial product. In this study, chicken fat, which is rich in unsaturated fatty acids, including oleic acid (C18:1) and linoleic acid (C18:2), was enzymatically interesterified with corn oil to produce a soft spread. Two interesterified products, sample 16 (4% enzyme, 4:1 mole ratio of chicken fat to corn oil, 50°C and 42 h of the interesterification process) and sample 17 (4% enzyme, 2:1 mole ratio of chicken fat to corn oil, 30°C and 42 h of the interesterification process), were selected based on the highest SFC at 30oC which were close to SFC values of commercial product. A morphological study showed that the final products had smaller and less dense fat particles, which explained the lower melting temperatures and solid fat content (3.2 and 3.5% for samples 16 and 17, respectively, at 20°C) compared to the commercial products (9.7, 6.8 and 7.7% for products A, B and C, respectively, at 20°C). However, both sample 16 and 17 had similar thermal properties to a vegetable-oil-based commercial product, with melting enthalpies (ΔH) of 58.45 J/g and 71.40 J/g, and were fully melted at 31.40°C and 35.41°C, respectively.
A study was carried out to determine the effect of enzyme concentration, temperature and incubation time of bromelain on nitrogen content (NC) and degree of hydrolysis (DH) of hydrolysate from cockle (Anadara granosa) meat wash water. Protein precipitation of cockle meat wash water was conducted at pH 4. The precipitate was then hydrolyzed using bromelain at concentrations of 0.5, 1.5 and 2.5% (enzyme/substrate). The best enzyme concentration was subsequently used to study the effect of incubation temperature at 30, 45 and 60°C. The best temperature was then used to determine the effect of incubation time at 0, 24 and 48 hours. Increasing bromelain concentration from 0 to 2.5% produced an increase in NC and DH. Similarly, increasing the incubation time from 0 to 48 hours also increased the value of NC and DH. However, while the increasing of incubation temperature from 30 to 60°C produced an increase in NC, no significant difference was observed for DH.
The objective of this study was to determine the physicochemical properties of pink guava (Psidium guajava) puree and its anti-hypertensive effect on Spontaneous Hypertensive Rats (SHR). Antioxidant activities of pink guava puree in water and ethanol extracts, based on 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, were 1.43±0.04 mg/gfm and 0.28±0.01 mg/gfm, respectively. A total of 24 male SHRs were divided into a control group, CG, and 3 treatment dosage groups [low dose group, LDG (0.5 g/kg body weight/day), medium dose group, MDG (1.0 g/kg body weight/day), and high dose group, HDG (2.0 g/kg body weight/day)]. Final body weights for treatment dosage groups were lower [MDG (313.01±31.25 g), HDG (318.56±17.96 g), LDG (320.01±22.70 g)] compared to CG (331.08±41.29 g). Final systolic blood pressure values from the beginning and the end of the experiment in MDG and HDG were 231-179 mmHg and 246-169mm Hg, respectively. These results were significantly lower when compared with CG (241-223 mmHg) from the beginning until the end of the experiment. As a conclusion, these results showed that pink guava puree has anti-hypertensive properties.
Rambutan (Nephelium lappaceum) peel is a potential source of antioxidant. As rambutan is a seasonal fruit, a proper heat treatment prior to storage is necessary. Thus, this study was conducted to determine the effect of water and steam blanchings on browning enzymes and antioxidant activities of rambutan peel extracts. Rambutan from the variety of ‘Anak Sekolah’ were peeled and the peel was blanched in boiling water for 0, 2.5, 5 min and by autoclaving for 0, 5, 10 and 15 min. The residual peroxidase (POD) and polyphenoloxidase (PPO) activities, antioxidant activity (2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity), total polyphenol content (TPC) and peel extract colour were determined. The results showed that both water and steam blanchings significantly reduced (p < 0.05) POD and PPO activities. The results also indicated that the increase in the blanching period did not significantly reduce the enzyme activities further. In terms of antioxidant activity, the thermal pretreatment caused no significant difference in the contents of phenolic compounds, as well as the antioxidant capacity of the final product.
A study was carried out to observe the fermentation process for noni (Morinda citrifolia L.) extract by Saccharomyces cerevisiae. The experiment was based on a central composite rotatable design (CCRD) employing 5 center points with augmented axial and factorial points resulting in 30 runs. The M. citrifolia extract was fermented with different combination of substrate concentration (40, 50, 60, 70 and 80%) (w/v), inoculum size (0, 1.5, 3, 4.5 and 6%) (v/v), temperature (30, 33.5, 37, 40.5 and 44oC) and fermentation time (0, 1.5, 3, 4.5 and 6 days). Five physico-chemical characteristics which include pH, titratable acidity, turbidity, total soluble solids and total polyphenol content were measured. Results showed that all the responses could be well represented using statistical models. For pH, only fermentation time was found to be not significant, while for titratable acidity and total polyphenol content, the effects of substrate concentration and fermentation time were significant. The effects of inoculum size and temperature level were found to be significant for turbidity. For total soluble solids, only the effect of substrate concentration and inoculum size were found to be significant.
Cockle (Anadara granosa) meat wash water precipitate was hydrolyzed using bromelain. Experiments were carried out to determine optimum conditions for temperature, enzyme concentration and hydrolysis time using response surface methodology (RSM) based on a central composite rotatable design (CCRD) to obtain the highest value of nitrogen content (NC) and degree of hydrolysis (DH). Results revealed that the optimum conditions for temperature, enzyme concentration and hydrolysis time were 33.7°C, 1.45% (E/S) and 28.42 hrs, respectively. At the optimum condition, hydrolysis of cockle meat wash water precipitate using bromelain resulted in a NC of 0.6% and DH of 48%. The NC and DH were significantly influenced by temperature, enzyme concentration and hydrolysis time. When the bromelain concentration, hydrolysis time and temperature were increased, the values of NC and DH also increased. The hydrolysate produced contained flavor compounds found in clam and oyster which were 3-methylbutanol and 1-pentanol. The compound 3-MCPD was not found in the hydrolysate.
This study was aimed to evaluate the effect of soursop (Annona muricata L.) extract on Sprague-Dawley rats subjected to in vivo 28-day repeated doses. The extract was given to the study group via force feeding. In the 28-day study, Annona muricata L. extract was dosed at 0 (CD, control dose), 0.5 (LD, low dose), 1.0 (MD, medium dose), 2.0g/kg (HD, high dose) body weight. For control group, distilled water was given to the animals. Administration of Annona muricata L. extract did not cause negative effect in blood hematology even though a statistically significant (p
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.
Anhydrous milkfat (AMF) was fractionated to obtain a series of high-melting milkfat fractions (HMF). Solid fat content (SFC) of HMF as determined by nuclear magnetic resonance (NMR) was in the range 37.6-43.6% and 21.2-27.5% measured at 20 and 30 degrees C, respectively. The HMF have a higher melting characteristic compared to AMF as analyzed by differential scanning calorimetry (DSC) with melting enthalpies of 92.2-105.0 J/g and melting peak temperatures of 39.3-41.5 degrees C. The AMF was also blended with soft palm stearin (SPOs and/or hard palm stearin (HPOs)) according to a three conventional component mixture design which providing suitable formulations for HMF. This represented three selected blends of AMF:SPOs:HPOs at three different proportions (70:15:15, 60:30:10 and 50:45:5), having SFC and DSC melting characteristics of HMF. The study revealed that higher-melting characteristics of AMF could be achieved equally well by using both fractionation and blending techniques.