In vitro and in vivo evaluation of Prosopis cineraria (khejri tree) leaves for their preservative potential in minced mutton

With an objective to extend the shelf life with improved microbial safety by natural means without compromising sensory attributes, lyophilised khejri tree leaf extract (LKE) was evaluated in vitro and in vivo. The LKE was subjected to preliminary scrutiny followed by FTIR mediated analysis and RP-HPLC and then its antioxidant activity was accessed. Five batches of minced mutton were prepared as C-1 (negative control with no LKE or BHA), C-2 (positive control with 200 ppm BHA), T-1 (0.05% LKE), T-2 (0.1% LKE), and T-3 (0.5% LKE). FTIR analysis showed C=O-CH3, C=C, C-O, and O-H peaks at 1028, 1609, and 1445 cm(-1) wave numbers, respectively. The LKE was found to have six phenolic compounds namely p-hydroxybenzoic acid, gallic acid, syringic acid, p-coumaric acid, ferulic acid, and sinapic acid. In minced mutton, LKE was found to be significantly (p = 0.05) more effective preservative than BHA at 0.5% level of incorporation in terms of TBARS value, tyrosine values, and microbial quality. During storage, the decrease in ERV and increase in total plate count were at a slower rate in treated samples and were devoid of coliform counts. However, sensory attributes at 0.5% LKE incorporation level were negatively affected and imparted a greenish tinge to minced mutton. The present work concluded that LKE might be incorporated without compromising sensory attributes. Further, preservative effects at 0.1% level were at par with BHA (200 ppm) and extended the minced mutton's shelf life up to 9 d at refrigerated temperature.