VALUE-ADDING FACTORS IN COLD-PRESSED EDIBLE SEED OILS AND FLOURS

Abstract

This study examined cold-pressed edible seed oil and flour from fruit and other plant sources for value-adding components and properties. The tested fruit seeds included black raspberry, red raspberry, boysenberry, marionberry, blueberry, cranberry, pinot noir grape, and chardonnay grape. The other seeds included onion, parsley, cardamom, mullein, roasted pumpkin, and milk thistle. The oils were examined for fatty acid profile, carotenoids, tocopherols, total phenolic content (TPC), oxygen radical absorbance capacity (ORAC), DPPH scavenging activity, oxidative stability index (OSI), peroxide value, refractive index, density, and color. The flours were tested for total fat, fatty acid profile, TPC, total anthocyanin content, chelating capacity, HT-29 cancer cell antiproliferation, ORAC, DPPH, and hydroxyl radical scavenging. All of the fruit seed oils contained significant levels of alpha-linolenic acid (18:3n-3) while none of the other seed oils contained a significant amount. The range of alpha-linolenic acid in the fruit seed oils was 19.6 to 32.4 g/100 g with red raspberry seed oil having the highest concentration. Zeaxanthin was the primary carotenoid in all seed oils and comprised approximately 79% of the combined total. Pumpkin seed oil contained the highest concentration of Beta-carotene at 6.0 mg/kg, and onion contained the most alpha-tocopherol from 498-692 mg/kg. Parsley and cardamom seed oil extracts had very high ORAC values of 1,100 and 942 micromol trolox equivalents (TE) per g oil, respectively, and their OSI were not determinable under experimental conditions. Among the seed flours, cranberry was the only sample that contained significant alpha-linolenic acid having 30.7 g/100 g oil, while the parsley seed flour sample contained 86.2 g/100g oleic acid (18:1n-9) and was significantly higher than all others. Milk thistle and chardonnay seed flour extracts had ORAC values of 1131 and 1076 TE micromol/g flour, respectively, and both significantly inhibited the growth of HT-29 cells at 6 mg/mL media. The chardonnay sample killed all cells following 24 h. The obtained data suggests the potential value-adding use of these seed oils and flours as dietary sources of special fatty acids, carotenoids, tocopherols, antioxidants, and antiproliferative agents, for optimal human health.