Physico-chemical and sensory acceptance of Carica papaya leaves extract edible O/W emulsion as prospective natural remedies

Abstract

Carica papaya Linnaeus commonly known as papaya is widely grown in Malaysia as a herbaceous plant with phytochemicals for a variety of use, particularly in the medical field. The therapeutic medicinal way of treating dengue fever using papaya leave extract mainly involves consumption a raw concoction and is very distasteful. Therefore, a study was carried out to develop stable emulsion with an acceptable taste through a ternary phase diagram system (TPDS), which comprised virgin coconut oil (VCO), isolated whey protein (WPI) and Carica papaya leaves extract (CPLE). The TPDS was developed using Chemix Software version 3.6 to identify the existence of homogenous phase region. In the first phase, a total of 11 selected samples (named as A to K) with concentrations ranging from 20% to 30% (w/w) of WPI from the homogenous phase region were used to select the best emulsion selection. Sample I with a composition of 25, 30 and 45% (w/w) comprising VCO, WPI and CPLE was selected and considered as the best and stable emulsion. In the second phase, sample I (renamed as sample M) underwent an addition of + 2% (sample L) and reduction of −2% (sample N) VCO. Analysis was carried out such as emulsion stability test (creaming index), pH value, viscosity, color and storage stability (4, 28 and 45 °C). The control sample was CPLE without any VCO or WPI. Sensory evaluation was also conducted to handpick the best formulation favored by 30 panellists. The sensory evaluation was conducted on samples L, M, N and CPLE using 7-point hedonic scale for preference on color, viscosity, odor, bitterness and overall acceptance attributes. The results showed that centrifugation test exhibited a stable emulsion for all the three samples (p > 0.05) L, M and N. In fact, there were differences between all the samples (p < 0.05) for pH, viscosity, and coloration of L* and b* values. For the storage stability test, all formulations were stable at 4 °C and there were no creaming layer and color changes developed except for sample L which was considered unstable at 28 °C and 45 °C. As for sensory preference, the color and bitterness was considered similar as compared to control (p < 0.05) except viscosity, odour and overall acceptance. In conclusion, sample N with compositional concentrations of 23% (w/w) VCO, 32% (w/w) WPI and 45% (w/w) CPLE was considered the most acceptable emulsion as it did not develop immiscible creaming layer and color changes at 4 °C and 28 °C. Based on the selected formulation, at least 270 ml emulsion by taking 3 tablespoons daily for 3 days in a row is needed as recommended by the Ministry of Health (MOH) in helping to increase the chances of curing dengue fever.