Bleaching techniques impact on some quality parameters in two different cold‐pressed oils obtained at farm scale

The consumption of cold-pressed oil, such as linseed (Linum usitatissimum L.) and hemp (Cannabis sativa oil has increased recently. In these oils obtained on the farm, a large number components able to affect quality (mainly chlorophylls) are present. Given this, an experiment was conducted with following aims: (1) compare different bleaching methods by applying ultrasound waves earths in hempseed (2) evaluate effect types (acid-activated natural) amount (2% 4%) processing temperatures (60 80°C) utilizing method alone. Regarding any methodologies adopted must not include treatment, high reached determine levels oxidation detriment oil. Concerning natural earths, especially at farm level, should be preferred, because addition removing chlorophyll satisfactorily, when used 4% even lowest temperature (60°C), improvement stability nutritional value (Vit. E) observed. Practical applications use ultrasound, applied together is considered interesting efficient method, order remove several pigments many vegetable oils, exception fact, during process determines (120°C) that characterized very percentage (> 55%) α-linolenic acid, negatively affects formation quantity primary products, evidenced peroxide values. activity carried out level particular, preferred acid-activated ones. latter, despite demonstrating effective efficiency for few specific pigments, could increase free fatty acids, reduce antioxidant compounds (tocopherols) naturally present, release undesirable contaminants