Résumé:
This work is interested in studying the effect of diet and lasting conservation of the quality of butter manufactured traditionally. The butter was made from the milk collected from two region (Zemoura and Aïn Nouïssy ) . The research was carried out using two factors namely; food (concentrate, green fodder) and conservation of hard has a refrigeration temperature of 4 ° C (D0 to D21). Biochemical analyzes of the butter concerned the dry matter, water and saponification , as well as the evolution of the peroxide value , acid value and the degree of lipid peroxidation (TBARS ) , also analyzes physicochemical and microbiological milk have harvested was conducted to ascertain the state of the milk. The diet factor and conservation is a highly significant effect ( P <0.01) on the indices (peroxide , acid saponifaction ) and lipid oxidation (TBARS ) of butter during the period storage of the product. The results show an evolution of peroxidation of the butter in two areas of D0 to D21 with (7.33 μg to 29.3μg) for the region Zemoura and increased (14.65μg to 29.96μg) to the region of Aïn Nouïssy . Thus , we see an increase in acid value ( 0.88mg to 1.12) in the butter from a concentrate -based diet ( Zemoura ) and ( 0.68mg to 1.07mg ) for butter coming from a feed from concentrate and green fodder ( Aïn Nouïssy ) , hence the evolution we observe a lipolysis (TBARS ) 7 times for butter in both regions. Regarding the butter saponification , the results allowed to infer that diet influences the saponification , the content is higher in the butter of the region Aïn Nouïssy and which are 64.51mg / g , knowing that the content of the saponification value for butter of Zemoura region is 35.05mg / g. A high content of total phenolics was recorded in the methanol extract is concentrated (39.11 mg OCT / g MS) against (31.90 mg OCT / g MS) for the extract of green fodder. According to the DPPH test , the results showed that the extract of the concentrate has a better inhibitory anti -radical activity of DPPH with the lowest IC50 ( 18,04mg / ml ) followed by green fodder which extract inhibitory anti -radical activity of DPPH is IC50 ( 18.53mg / ml). Regarding sensory analysis shows that the butter of Zemoura has a white color and smell and taste nice knowing that the butter of the region Aïn Nouïssy has a yellow color and smell and taste rancid.
