MVSc

The present study on the tenderisation of buffalo meat by calcium chloride marination was designed to assess the effect of marination on tenderness and other organoleptic qualities of meat and to compare the effects with those of natural ageing.

Samples of longissimus dorsi muscle between 9th and 12th thoracic vertebrae from 14 healthy crossbred Murrah buffaloes of 4 – 8 years old were collected. They were assorted for three treatments, viz., samples neither aged nor calcium chloride marinated; and stored at room temperature for 6 h postmortem (NAM), samples aged only (A), samples which are marinated (AM). Samples of A and AM were stored at 2-4o C. The aerobically packaged samples for the treatment AM after 24 h of storage were marinated by injection with 200 mM calcium chloride solution (5% w/w) at multiple sites.

The pH, WHC, cooking loss, color, MFI, WBSF and sensory quality attributes such as juiciness, ease of fragmentation, amount of connective tissue, overall tenderness, flavour intensity and colour of the steaks were assessed. The samples for the treatment NAM were subjected to the study at 1 h and 6 h and the steaks from A and AM at 1 h, 6 h and on days 1, 2, 4, 6 and 8.

The pH of the steaks was not affected by CaCl2 marination. It followed the normal postmortem pattern, with a pH of 6.7 ± 0.01 at 1 h in all treatments. The ultimate pH of 5.6 reached on day 1 was significantly lower (P < 0.05) than on all days, which gradually increased until day 8 in treatments A and AM. The samples followed a normal rigor with sufficient amount of m-calpain and the increase in pH was due to the accumulation of products of proteolysis.

The WHC at 1 h was 0.37 ± 0.021 which declined to a significantly lower (P < 0.05) value of 0.31± 0.021 at the ultimate pH on day 1. This remained almost static till day 8 in both treatments A and AM. On day 1 the pH and calcium induced shrinkage caused loss of water. Later changes in the cytoskeleton improved WHC by removing rigor induced shrinkage of myofibrils. WHC was not significantly affected by calcium chloride marination.

The percentage of cooking loss increased significantly (P < 0.05) on day 1 and thereafter it remained static till day 8. Calcium chloride was not found to affect the percentage of cooking loss. The comparatively higher loss observed in the study could be attributed to the lack of external fat covering and marbling in the buffalo LD steaks.

Ageing is found to improve the colour of fresh meat from day 1 onwards. But calcium chloride marination did not have any additional effect on the colour of aged meat. The decline in postmortem pH to 5.6 on day 1 contributed to higher L, a, b values which increased the light scattering properties. On subsequent days, L, a, b values remained without significant changes. This could be due to the antioxidant action of amino acids and dipeptides formed during postmortem proteolysis, which preserve the methmyoglobin reducing activity.

In treatments A and AM the MFI followed a gradual significant decrease (P < 0.01) from 768.0 ± 40.52 to 541.78 ± 34.63 on day 1 and day 8, respectively in aged steaks. While in marinated it declined to 465.28 ± 29.79 on day 8. Significantly lower (P < 0.01) value of 630 ± 42.88 on day 2 in marinated samples was comparable to that in the aged samples on day 4, indicating the early achievement of tenderness in marinated samples. MFI varied little with ultimate pH. MFI is deemed as a very useful indicator of meat tenderness particularly when sample size is smaller for the determination of shear force or sensory evaluation.

Significantly highest (P < 0.01) WBSF value of 11.37 ± 0.61 obtained on day 1 could be attributed to rigor induced shortening. The values declined significantly in treatments A and AM. The values obtained for the marinated steaks were significantly lower (P < 0.01) than the aged samples on all days postmortem. It reduced from 10.48 ± 0.48 at 1 h postmortem to 4.88 ± 0.45 in a course of 8 days. This indicated a 53.44% reduction in values from 1 h to day 8, while in aged sample only a 35.59% reduction was noticed in a course of 8 days.

The sensory panel evaluation of organoleptic qualities showed that calcium chloride marinated steaks significantly improved (P < 0.01) in the scores for the different attributes studied on each day of ageing. No flavor problems or alterations in cooked color were noticed at 200mM CaCl2.
Correlation studies in between MFI and WBSF revealed a significant positive correlation (P < 0.01) with r = 0.85 in A and 0.84 in AM on all days from 1 to 8. This indicates that MFI could be used as an indicator of tenderness of fresh meat rather than cooked. WBSF and MFI were strongly correlated with the overall tenderness measured by taste panel evaluation. The overall tenderness was more negatively correlated with SF (r = 0.70) rather than MFI (r = 0.65).
The tenderness and other organoleptic qualities of buffalo longissimus steaks could be improved significantly by post-rigor marination with 200mM CaCl2 (5 % w/w) on day 1 and subsequent ageing at 2 – 4o C for 4 – 8 days. The tenderness improved by 53.44 per cent in marinated steaks as against 35.59 per cent in those aged without marination. The improvement in tenderness could be attributed to the activation of μ- and m-calpain by calcium ions and the autolysis of calpastain at 2 - 4o C of ageing.