Optimizing microencapsulation of nisin with sodium alginate and guar gum.

Nisin is a widely used bacteriocin active against gram positive bacteria and is also reported to be active against some gram negative bacteria. Incorporation of nisin into food systems is another challenge as directly added nisin is prone to inactivation by food constituents. Encapsulation of nisin has been done so far in liposomes which is rather an expensive technology involving multiple processes. Other cost effective alternatives with good encapsulation efficiency and better control release properties are sought. Alginate is useful as a matrix for entrapment of bioactive compounds. Present study was aimed at optimizing conditions for microencapsulation of nisin using calcium alginate as primary wall material and guar gum as filler at different air pressures using response surface methodology. The optimum conditions were: sodium alginate concentration (2 % w/v), guar gum concentration (0.4 % w/v), and air pressure (0.5 bar gauge). The encapsulation efficiency of nisin in microcapsules produced under optimal conditions was 36.65 %.

Antibacterial activity of aqueous extract of pomegranate peel against Pseudomonas stutzeri isolated from poultry meat.

In this study antibacterial activity of pomegranate peel (PPE) was evaluated against bacteria isolated from poultry meat. The bacteria were identified using 16S rRNA gene and DNA sequencing. Results of molecular characterization showed that the bacteria isolated were having 100% homology with the Pseudomonas stutzeri strain CTSP36 and further analysis showed that sample sequence clustered with the P. stutzeri strain CTSP36. Antibacterial activity of PPE was demonstrated by clear zone of inhibition in plates inoculated with extract. The diameter of inhibition zones were significantly (p < 0.05) higher in PPE as compared to standard antibiotic discs used (tetracycline, vancomycin and streptomycin). Results of broth dilution assay also revealed that PPE at 1%, 5% and 10% were effective in inhibiting bacterial growth in test plates. Further, a decrease in the growth of bacterial cells and a gradual decline in protein content of bacterial cells were also observed when bacterial culture was grown with different concentration of PPE along with a control. These results showed the potential application of pomegranate peel extract as antibacterial agent against P. stutzeri.

Nondestructive methods for quality evaluation of livestock products.

The muscles derived from livestock are highly perishable. Rapid and nondestructive methods are essential for quality assurance of such products. Potential nondestructive methods, which can supplement or replace many of traditional time consuming destructive methods, include colour and computer image analysis, NIR spectroscopy, NMRI, electronic nose, ultrasound, X-ray imaging and biosensors. These methods are briefly described and the research work involving them for products derived from livestock is reviewed. These methods will be helpful in rapid screening of large number of samples, monitoring distribution networks, quick product recall and enhance traceability in the value chain of livestock products. With new developments in the areas of basic science related to these methods, colour, image processing, NIR spectroscopy, biosensors and ultrasonic analysis are expected to be widespread and cost effective for large scale meat quality evaluation in near future.

Tenderizing effect of blade tenderizer and pomegranate fruit products in goat meat.

Toughness of goat meat is a major problem with regard to consumer acceptance. Keeping this in view a blade tenderizer was developed for tenderization of goat meat. Pomegranate fruit products were also explored for tenderization effect on goat meat. Tenderization of goat meat with pomegranate seed powder improved the textural properties marginally with slight adverse colour change and taste. Samples treated with PRP got lower score for colour in sensory evaluation and there was adverse effect on taste of treated meat. Blade tenderization and 4% PSP proved better for tenderization and were compared with control and 0.2% papain in goat meat chunks. The cooked samples treated with papain and blade incisions got better sensory scores and required lesser shear force compared to 4% PSP and control. Overall the papain treated meat was superior in terms sensory attributes followed by blade incision and PSP. The results suggested that the blade incisions can be used for tenderization of goat meat. Pomegranate seed powder maybe considered for mixing with other spices to marinate goat meat mainly for its beneficial effects.