RESEARCH ON EXTRACTION TECHNOLOGY TO IMPROVE YIELD AND QUALITY OF OIL FROM GAC ARIL (MOMORDICA COCHINCHINENSIS SPRENG L.)

Abstract

1. INTRODUCTION
Gac (Momordica cochinchinensis Spreng L.) belonging to the family Cucurbitaceae is an indigenous Vietnamese fruit-bearing plant. Its fruit flesh contains 1 - 3 mm thick, red, soft, and sticky aril, which covers black seeds and makes up about 25% of the fruit weight [1].
Gac aril has an oil content of about 38% - 40% (as related to absolute dry matter). This oil is a rich source of beta-caroten and lycopen, containing 128 mg%, and 170 mg% of each, respectively. The alpha-tocopherol content in the pulp was found to be 76.3 mg/g [2]. Because of its valuable constituents as mentioned above, Gac fruit oil is studied and used to create functional food and pharmaceutical products.
A 30-day controlled supplementation trial carried out in Vietnam found that daily consumption of ‘‘xoi gac’’, a traditional Vietnamese sticky rice dish containing Gac aril, significantly improved plasma levels of retinol, alpha-caroten, beta-caroten, and lycopen in pre-school children [3]. Researchers also investigated the potential of Gac fruit to prevent and treat cancers and vitamin A deficiency, where by juice extracted from dried Gac was found to reduce the tumour weights in mice by 23.6% [4]. The content of lycopen in Gac pulp as reported by this study (408 mg/g) is much higher than that usually found in tomatoes (about 25 mg/g) [5].
Currently, Gac aril oil production is mainly carried out by traditional mechanical expression with a screw press, but  this method gives low yield and quality (especially in regard to the content of beta-caroten and lycopen). This paper describes a new method to obtain Gac aril oil with high extraction yield and oil quality.