EFFECT OF ONION (ALLIUM CEPAL.) EXTRACT ON MICROBIOLOGICAL QUALITY OF REFRIGERATED BEEF MEAT

Effect of onion skin powder on color, lipid, and protein oxidative stability of premade beef patty during cold storage

The impact of premade beef patty (BBP) with red onion skin powder (OSP) at 0, 1, 2, and 3% levels on color, lipid, and protein oxidative stability, and infection degree of microorganisms during cold storage was investigated. The objective was to determine the effect of color by L*, a*, b*, and the content of MetMb. The inhibitory effect of OSP on the oxidation of lipid and protein was studied based on TBARS and the carbonyl content of protein in samples at different storage times. TVB-N content was used to characterize the degree of infection of microorganisms and their effect on meat quality. The results showed that the addition of OSP reduced the pH, L *, a*, and b * values of BBP, and improved the hardness, springiness, gumminess, and cohesiveness of BBP, but had no significant effect on the chewiness of BBP (p > 0.05). After 12 days of storage, the carbonyl group and TBARS content in the BBP supplemented with 3%OSP was significantly lower than that in the control group (p < 0.05). Furthermore, the addition of OSP significantly inhibited the TVB-N increase during beef patty storage. These results indicated that OSP has a good research prospect as a natural antioxidant or preservative.

Gelatin/carboxymethyl cellulose edible films: modification of physical properties by different hydrocolloids and application in beef preservation in combination with shallot waste powder

In this work, a gelatin/carboxymethyl cellulose (CMC) base formulation was first modified by using different hydrocolloids like oxidized starch (1404), hydroxypropyl starch (1440), locust bean gum, xanthan gum, and guar gum. The properties of modified films were characterized using SEM, FT-IR, XRD and TGA-DSC before selecting of best-modified film for further development with shallot waste powder. SEM images showed that the rough or heterogeneous surface of the base was changed to more even and smooth depending on the hydrocolloids used while FTIR results demonstrated that a new NCO functional group non-existent in the base formulation was found for most of the modified films, implying that the modification led to the formation of this functional group. Compared to other hydrocolloids, the addition of guar gum into the gelatin/CMC base has improved its properties such as better color appearance, higher stability, and less weight loss during thermal degradation, and had minimal effect on the structure of resulting films. Subsequently, the incorporation of spray-dried shallot peel powder into gelatin/CMC/guar gum was conducted to investigate the applicability of edible films in the preservation of raw beef. Antibacterial activity assays revealed that the films can inhibit and kill both Gram-positive and Gram-negative bacteria as well as fungi. It is noteworthy that the addition of 0.5% shallot powder not only effectively decelerated the microbial growth but also destroyed E. coli during 11 days of storage (2.8 log CFU g-1) and the bacterial count was even lower than that of uncoated raw beef on day 0 (3.3 log CFU g-1).

The effects of dietary quercetin supplementation on the meat quality and volatile profile of rabbit meat during chilled storage

Thirty-four New Zealand White rabbits of both sexes were fed a control or supplemented (2 g/kg quercetin dihydrate) diet from weaning until slaughter (13 weeks). After post-mortem chilling, excised and minced Longissimus thoracis et lumborum muscles were stored at 3.2 °C under oxygen-permeable wrapping for 1, 3 or 5 days. Colour, pH, lipid oxidation (TBARS), antioxidant capacity (FRAP), volatile profile (day 1 and 5) and microbial count (day 5) were determined. Quercetin reduced alkane (day 5) and hexanal (day 1) concentrations, but otherwise had minimal antioxidant effect, and did not benefit microbial quality, and thus did not substantially improve the shelf-life. The sex effect was similarly limited. Overall, the pH increased and FRAP decreased during storage, but TBARS did not change and discolouration seemed delayed. The volatile profile was dominated by esters, alcohols and heterocyclic compounds, and while it changed during storage, lipid oxidation products did not increase as expected, suggesting that rabbit meat may have relatively active reducing mechanisms.

Dietary supplementation of different parts of Andrographis paniculata affects the fatty acids, lipid oxidation, microbiota, and quality attributes of longissimus muscle in goats

The effects of dietary supplementation of different parts of Andrographis paniculata on fatty acids, lipid oxidation, microbiota and quality attributes of Longissimus thoracis et lumborum (LTL) muscle in goats were assessed. Twenty four, entire Boer bucks (4 months old; 20.18 ± 0.19 kg BW) were randomly allotted to either a basal diet without additive (AP0), a basal diet + 1.5% Andrographis paniculata leaves (APL) or a basal diet + 1.5% Andrographis paniculata whole plant (APW). The bucks were fed the diets for 100 d and slaughtered. The LTL muscle was subjected to a 7 d chill storage. The AP0 meat had higher (p < .05) concentration of C16:0 and C18:0 than the APW and APL meat. The concentrations of total C18:1trans, total CLA, C18:1n-9, C18:2n-6, C18:3n-3 and C20:5n-3 were higher (p < .05) in APL and APW meat than the AP0 meat. Diets had no effect (p > .05) on muscle glycogen, pH, drip loss, chemical composition and lactic acid bacteria count. Cooking loss, shear force, and TBARS values were lower (p < .05) in APL (23.98%, 0.76 kg, 0.12 mg MDA/kg) and APW (24.53%, 0.80 kg, 0.15 mg MDA/kg) meat compared with AP0 (26.49%, 1.13 kg, 0.23 mg MDA/kg) meat. Meat redness was higher (p < .05) in APL (13.49) and APW (12.98) than AP0 (10.86). Sensory scores for juiciness, tenderness, and overall acceptability of APL (7.92, 7.88, 7.89) and APW (7.90, 7.08, 7.77) meat were higher (p < .05) than that of the AP0 (5.38, 5.95, 5.41) meat. Total viable counts and populations of Pseudomonas spp, Escherichia coli and Enterobacteriacea were higher (p < .05) in AP0 meat than in APL and APW meat. The APL exhibited higher (p < .05) antimicrobial potential than the APW. Chill storage affected (p < .05) the physicochemical properties, lipid oxidation and microbial counts in chevon. Dietary APL and APW enhanced the beneficial fatty acids, quality attributes and oxidative stability, and reduced microbial counts in chevon.

Effects of plant extracts and essential oils as feed supplements on quality and microbial traits of rabbit meat

The effects of dietary supplementation of onion, cranberry,  strawberry and essentials oils on meat quality were analysed. Five groups of 48 Grimaud female weaned rabbits received the supplemented or the control ration; the experimental unit was a cage of 6 rabbits. Each experimental diet contained 10 ppm of added active ingredients.  Rabbits were fed with the experimental diets for 4 wk before determining slaughter and carcass traits and determining the pH at 1 and 24 h post mortem (pHu) of the <em>Longissimus dorsi</em> (LD) and the <em>Biceps femoris</em> (BF) muscle, left and right, respectively. Cooking loss, drip loss and L*, a* and b* color parameters were obtained of the right<em> </em>LD and for ground meat and antioxidant status (TBARS, DNPH, Folin Ciocalteu). Only the pHu of the LD muscle for the strawberry supplemented group was significantly lower when compared to the control group (P=0.04). However, we note that for the pH of the LD, the average was less than 6 for the meat of animals who received a diet enriched in polyphenols, compared to the control group. Plant extract supplementation did not influence meat quality traits, growth performance or oxidative stability. But under aerobic and anaerobic conditions, our results indicate that diet supplementation with extracts rich in polyphenols, especially with essential oils, had a small bot sporadic positive effect in reducing bacterial microflora compared to the control group (P&lt;0.05). In conclusion, plant extracts and essential oils can be used in a rabbit diet without adverse effects on performance and meat quality traits. This effect could be optimized by investigating higher doses.