A study on the shelf life of cookies incorporated with sapota and beetroot leaf powders

The addition of edible fiber could affect the shelf life of cookies, which can have a positive or negative impact depending on the source of fiber. This study is in continuation of two previously published papers to investigate the storage stability of cookies incorporated with 4.5% beetroot leaf powder (BLP), with 7% sapota fiber powder (SFP) and reference cookies during 15 months at ambient temperature by analyses of physicochemical, microbial and sensory properties on each specified month using international standard methods. It was found that with increasing storage period, there was an increment in moisture content, peroxide value, free fatty acids and microbial population including total aerobic bacteria and yeast and mold colonies of all cookies; the lowest values being for cookies with 7% SFP (5.70%, 4.12 mEqO₂/1000 g cookie's fat, 1.47%, 2.73 and 2.36 log CFU/g dried cookie, respectively). In contrast, the reverse trend was found in pH value. At the end of storage, a significant difference (p ≤ 0.05) was observed between reference cookies and other cookies regarding moisture content, peroxide value, free fatty acids and overall sensory acceptability; the quality of cookies supplemented with 7% SFP being desirable, followed by cookies with 4.5% BLP, and then reference cookies.