Organoleptic Degradation of Herbal Surface Cleaners: Tracking Odour and Visual Changes during Accelerated Storage

Abstract

The organoleptic properties-odour, appearance and colour of a herbal surface cleaner which affect consumers' perception towards the product and viability were very significant quality attributes [6,11]. In this investigation, organoleptic degradation profile of neem ( Azadirachta indica) and lemon (Citrus limon) based herbal surface cleaners at 3%, 4%, 5%, 6% and 7% and temperatures at 25oC, 30oC, and 45oC were studied for 4-weeks in accelerated conditions. These preparations were assessed on a weekly basis by a trained sensory panel according to scale evaluation chart for odour, appearance and color together with the measurements of pH, grittiness, foam stability and microbial count (Total bacterial count, Total fungal count). Results showed consistent progressive degradation for organoleptic properties across all preparations and factors affecting rate of deterioration are temperature and concentration (p < 0.05). At 45oC, the formulations with 3% concentration completely degraded with odor changes from "Fresh, Citrus Neem" to "Foul" for 4 weeks. At least 6% of active ingredient concentrate showed good thermostability under stressing of temperature, where totally no pigment oxidation, or browning of the preparations. Positive correlation between increasing pH value of formula and the corresponding preservation on sensory odor score proved to have strongly negative linear correlated with r=-0.91, p<0.01 indicating as the pH of the matrix tends to alkaline after bio chemical degradation, lower odor score will be observed. Detection of odor change often proceeded the observation of precipitation and is used as an accurate indication for organoleptic failure under storage. Formulation with 5% concentration at 25oC exhibited the ideal physical properties, but formulation with less than 5% actively performed physical failures, function losses and microbiological failures under stress during storage. Combining a consistent sensory parameter and the tracking of pH drifts could be beneficial for quality control of such natural product (cleaning agents).