Producing Defatted Hybrid Catfish with High Protease Activity Via Optimization of Sc-CO2 Extraction Process

Fish viscera is a great source for recovering polyunsaturated fatty acids (PUFAs), proteins and digestive enzymes. However, the presence of lipids in fish viscera reduces the efficiency of extracting, isolating and purifying the enzymes. Supercritical carbon dioxide (Sc-CO2), a green solvent, is useful in substituting organic solvent defatting process. Sc-CO2 helps to remove the lipid in the viscera with minimal denaturing of the proteins and enzymes found in the defatted sample. The viscera of hybrid catfish (C. gariepinus × C. macrocephalus) in this study were defatted by the Sc-CO2 extraction process. The protease was then, extracted from the defatted viscera. This study aimed to optimize the pressure and temperature of Sc-CO2 in the defatted viscera. The optimization of Sc-CO2 parameters was based on the Central Composite Design (CCD) of Response Surface Methodology (RSM). Optimum points were observed within the variables of pressure (P): 17-25 MPa and temperature (T): 39-43 °C with constant CO2 flow rate (F) and extraction time (text) at 25 g/min and 30 min, respectively. The response variables were executed on the amount of fat residue and protease specific activity in the defatted viscera. The optimum Sc-CO2 parameters were found to be at P: 18.17 MPa and T: 41.33 °C with the highest protease activity of 77.51 U/mg and fat residue of 71.17 %. The coefficient of determination (R2) for protease specific activity and fat residue was 90.27% and 93.03%, respectively. The differences between the verification and predicted values for both responses were less than 5%.  Hence, the feasible optimum condition to produce a defatted sample with high specific activity at relatively low fat residue as predicted by the RSM in MINITAB statistical software version 16 was acceptable. Nevertheless, the ability of Sc-CO2 to defat the sample with minimal denaturing proteins and enzymes highlights the usefulness of this technology in substituting other organic solvents for the defatting process

Effect of different degree of deacetylation, molecular weight of chitosan and palm stearin and palm kernel olein concentration on chitosan as edible packaging for cherry tomato

The palm stearin and palm kernel olein (PSPKOo) blend (at 31%) was incorporated into chitosan of different degree of deacetylation (DD) (85 and 95%) and molecular weight (MW) (100,000 and 300,000 Da) to form films, and the films were evaluated in terms of particle size, diameter and stability of emulsion, as well as thickness and tensile strength. The chitosan with 85% DD (MW 300,000 Da) and 31% PSPKOo blend resulted in the strongest film, while this chitosan varied with 15.5 and 31% of PSPKOo blends compared to physical properties of film. Emulsion blend containing 85% DD (MW 300,000 Da) and 31% PSPKOo blend of chitosan gave the biggest particle size, highest viscosity and the most stable emulsion, resulting in the thickest film with the highest tensile strength (TS) and elastic modulus (EM). The film was applied on cherry tomato and stored at 20C for 9 days. The chitosan film with 85% DD (MW 300,000 Da) and 31% PSPKOo blend was the most effective in reducing weight loss and maintaining firmness and redness of cherry tomato compared to the other two films. Hence, palm stearin (PS) showed potential to be used as a moisture barrier in fruit coating

Inactivation Of Microorganisms In Skim Milk And Shredded Mozzarella Cheese Using High Pressure Carbon Dioxide And Nitrous Oxide

Inactivation of microorganisms with high-pressure carbon dioxide (HP-CO2) is emerging as an innovative process for the sterilization of biological materials. However, its application in milk processing poses a challenge since CO2-induced reduction in pH may lead to casein precipitation. High-pressure nitrous oxide (HP-N2O) has been suggested as an alternate choice for the processing of fluid milk. Agitated supercritical carbon dioxide (Sc-CO2) at 10.3 MPa and 35°C with 100 ppm peracetic acid (PAA) resulted in a complete 8- and 5-log10 inactivation of Escherichia coli and Bacillus atrophaeus spores in thin milk-films after 15 and 40 min, respectively. The treatment also resulted in partial milk-protein coagulation (55%) and thus possible applications of this approach may be in those processes where curd formation from sterile milk is beneficial. The HP-CO2 treatment at 10.3 MPa with 50 ppm PAA resulted in 2.6-, 5.4- and 9.2-log10 reductions of E. coli in agitated bulk milk after 120 min at 5, 15 and 25°C, respectively, whereas a 0.7-log10 reduction of B. atrophaeus spores was obtained at 25°C. The Fermi model was used to describe the inactivation kinetics of E. coli and B. atrophaeus. This strategy should be attractive for low-temperature ([LESS-THAN OR EQUAL TO]25°C) pasteurization of fluid milk. A 20-min treatment of skim milk with added nisin (150 IU/mL) using HP-N2O (15.2 MPa and 65°C) resulted in 8- and 8.6-log10 reductions of E. coli and Listeria innocua, respectively. ! Meanwhile, a 2.5-log10 inactivation of B. atrophaeus spores was obtained when lysozyme (50 [MICRO SIGN]g/mL) was also added and the temperature was increased to 85°C. There were no significant changes in the physico-chemical properties of the treated milk and no sub-lethally injured cells were detected following the treatment. Agitated Sc-CO2 at 9.8 MPa and 35°C with 100 ppm PAA synergistically resulted in the inactivation of major microbial groups in shredded Mozzarella cheese after 30-min of treatment. A >5-log10 reduction in the populations of E. coli, L. innocua, yeasts & molds and the total bacterial counts along with a 4-log10 reduction of Geobacillus stearothermophilus spores was achieved during storage for 21 days at 25°C.

Halal assurance at farm level in the poultry supply chain

Halal Assurance System (HAS) develop by JAKIM has undergone several revisions in its requirement since 2011. HAS is currently practised at the downstream of poultry supply chain focusing only on the slaughtering and production stage of chicken products. Despite of the importance and significance to comply the HAS’s halal critical point (HCP) at each step in poultry processing industry, there are still limited studies emphasizing the HAS the implementation at the upstream level. Thus, this study focuses on the qualitative methodology approach through documentation analysis to obtain sources of information on the importance of HAS and the elements of halal risk control (HRC) in broiler chicken farm activities. Finding shows that there are five elements in the broiler chicken farms that have been identified as HRC includes livestock food and drink, medical, farm biosecurity, infrastructure, and logistics. So, implementing of HAS in the broiler chicken farm is important to maintain the transparency and integrity of halal certification policies in the HRC at the upstream level of halal food supply chain. This study also suggested that HAS can be applied on other livestock sectors such as ruminant and fish for safeguarding the halal status of meat supply chain in Malaysia

Halal risk assessment in broiler hatchery operations

Halal risk assessment in the poultry industry mainly focuses on identifying halal risks at slaughtering and chicken meat processing. Yet halal risk at the early stage of broiler supply before being transferred to livestock farms has not been discussed intensely. This study explores an overview of egg-hatching activities in proposing the halal critical points (HCP) involved in hatchery operation. It was found that five activities in the hatching process had been identified as significant points of halal risk, which are egg receiving from breeder farms, egg incubation, chick disposal, vaccination of chicks, and logistics. A qualitative approach was used to gather information via document analysis and a semi-structured interview in describing and analyzing the halal hazards and risks associated in hatchery operations. The study emphasized that halal risk assessment could be carried out in the commercial broiler hatchery operation of other fowl, such as ducks or quail. Besides, give a positive impact on maintaining the halal integrity of meat sources to Muslim consumers

Angiotensin converting enzyme (ACE)-peptide interactions: inhibition kinetics, in silico molecular docking and stability study of three novel peptides generated from palm kernel cake proteins

Three novel peptide sequences identified from palm kernel cake (PKC) generated protein hydrolysate including YLLLK, WAFS and GVQEGAGHYALL were used for stability study against angiotensin-converting enzyme (ACE), ACE-inhibition kinetics and molecular docking studies. Results showed that the peptides were degraded at different cleavage degrees of 94%, 67% and 97% for YLLLK, WAFS and GVQEGAGHYALL, respectively, after 3 h of incubation with ACE. YLLLK was found to be the least stable (decreased ACE-inhibitory activity) compared to WAFS and GVQEGAGHYALL (increased ACE-inhibitory activity). YLLLK showed the lowest Ki (1.51 mM) in inhibition kinetics study when compared to WAFS and GVQEGAGHYALL with Ki of 2 mM and 3.18 mM, respectively. In addition, ACE revealed the lowest Kappm and Vappmax and higher catalytic efficiency (CE) in the presence of YLLLK at different concentrations, implying that the enzyme catalysis decreased and hence the inhibition mode increased. Furthermore, YLLLK showed the lowest docking score of −8.224 and seven interactions with tACE, while peptide GVQEGAGHYALL showed the higher docking score of −7.006 and five interactions with tACE