Phytosterols and γ‐oryzanol in rice bran oils and distillates from physical refining process

Abstract

Commercially available refined rice bran oil (RBO) contained high contents of phytosterol and c-oryzanol, that is, 858-1034 and 248-887 mg per 100 g oil, respectively. Although the crude rice bran oil (CRBO) had high contents of both phytochemicals (1362-1376 mg phytosterol per 100 g and 1599-1666 mg c-oryzanol per 100 g), physical refining process resulted in their reduction to 820-895 mg phytosterol per 100 g and 933-960 mg c-oryzanol per 100 g in RBO (P < 0.05). Both phytochemicals evaporated and accumulated in the deodoriser distillate (DD) to some extent during the deodorising step. Further distillation of DD using molecular distillation (MD) evaporated the free fatty acids (FFAs), resulting in the unevaporated fraction (UMD) having the acid values of 5.6-9.3 mg KOH g À1 . The UMD also contained 1585-3391 mg phytosterol per 100 g and 781-848 mg c-oryzanol per 100 g. Results suggest potential use of DD as the source of phytochemicals for further concentration by MD.

Rice Bran Oil Distillate, a Choice for Gamma-Oryzanol: Separation and Oxidative Stability Study

“…The concentration of γ-oryzanol in rice ban oil distillate was found to be less (0.83%) than that of crude rice bran oil (1.48%). Our results are in agreement with the results reported by other researchers for rice bran oil (1.1-1.7%, 1.6%) and rice bran oil distillate (0.79%, 0.8-%) (Gopala Krishna et al, 2001;Sawadikiat et al, 2014 …”

“…The purified fraction from column chromatography contain 0.83% of γ-oryzanol which is obtained from HPLC analysis (Table 2 and Figure 1). The result is comparable to the results reported for γ-oryzanol yield (0.84-1.14%) from deodorized distillate through molecular distillation (Sawadikiat et al, 2014). All the results related to the concentration of γ-oryzanol and its major individual components like cycloartenylferulate (1), 24-methylene cycloartanylferulate (2), Campesterylferulate (3) and Sitosterylferulate (4) are summarized in Table 2.…”

Phytochemical Content, Oxidative Stability, and Nutritional Properties of Unconventional Cold-pressed Edible Oils

“…The lowest level of total phytosterol content was detected in black cumin oil (44 mg/100g). The plant oils richest in phytosterols, which had more than 1 g of these compounds per 100 g of oil, are sea buckthorn seed oil, and rice bran oil [35,36], whereas the total amount of phytosterols in traditional plant oils such as rapeseed, sunflower, and soybean ranges from 300 mg/100g to 800 mg/100g [37]. The contribution of the most prevalent sterol, β-sitosterol, to the total sterol content in each oil was highest in apricot kernel oil (86%), followed by macadamia nut oil (84%), avocado fruit oil (79%), pine nut oil (77%), blackcurrant seed oil (67%), hemp oil (67%), safflower oil (65%), wheat germ oil (64%), dill seed oil (63%), poppy seed oil (61%), parsley seed oil (60%), black cumin oil, and milk thistle oil (45%-46%).…”

Production of Rice Bran Oil with Light Color and High Oryzanol Content by Multi‐stage Molecular Distillation

“…It has been regarded as the most suitable distillation method for separating and purifying heat-sensitive products such as: fatty accompaniments [11,12]; monoacylglycerols and diacylglycerols [13,14]; eicosapentaenoic acid and docosahexaenoic acid ethyl esters [15,16]; as well as for removing undesirable molecules [17]. Furthermore, molecular distillation also traditionally plays a significant role in oil refining (especially in oils with high FFA contents such as RBO) in the deacidification and deodorization processes [10,18,19]. The use of molecular distillation in these processes relies on the higher volatility of FFAs and oxidation product molecules relative to triacylglycerols.…”