Abstract:
The avocados (Persea Americana) of Hass variety, collected from Aatmara, Dhankuta
were subjected to oil extraction by screw pressing and solvent extraction. The extracted oil
were analysed for physiochemical properties like melting point, specific gravity, refractive
index, iodine value, saponification value and unsaponifiable matters. The oxidation rate at
room temperature (RT) for 45 days was studied for both oil using acid value (AV) and
peroxide value (PV) as stability indices at an interval of 9 days.
The proximate analysis of avocado fruit showed 70.03±0.085% moisture,
22.61±0.020% fat, 1.19±0.303% protein, 0.59±0.01% minerals, 0.98% carbohydrate and
4.6±0.264% crude fiber. The melting point, specific gravity, refractive index, iodine value,
saponification value and unsaponifiable matters were found to be 14.4±0.3°C, 0.875±0.01,
1.460±0.0005, 57.948±0.015 oil, 176.3±0.019 and 1.79±0.026 % for oil obtained by
solvent extraction of dried pulp, and 15±0.2°C, 0.901±0.001, 1.461±0.001, 70.6±0.0 oil,
154.793±0.023 and 1.83±0.30% for oil obtained by screw pressing of dried pulp
respectively. The oil yield was found to be 52.08% and 46.86% by solvent extraction
method and screw pressing method respectively. AV and PV of both oil significantly
increased (p < 0.05) with the increasing of storage time for 45 days. There was a
significant difference (p<0.05) in increment pattern of oils. Both oils maintained their AV
and PV within edible range till 45th day of storage at room temperature. Hence, avocado oil
obtained by both processes are edible till 45 days of storage at room temperature
Description:
A dissertation submitted to the department of Food Technology, Central Campus of
Technology, Tribhuvan University, in partial fulfillment of the requirements for the
degree of B. Tech in Food Technology
