Effect of Filtration Process on Oxidative Stability and Minor Compounds of the Cold-Pressed Hempseed Oil during Storage

Abstract

Cold-pressed hempseed oil (HO) has been increasingly exploited in the human diet for its excellent nutritional and healthy properties. However, it has a high content of polyunsaturated fatty acids (PUFAs) and chlorophylls, which inevitably accelerate its oxidative deterioration, especially in the presence of light. In this scenario, the filtration technology may ameliorate the oxidative stability of the oil, with positive effects on its nutritional quality and shelf life. Therefore, in this study, the oxidative stability and minor compounds of non-filtered and filtered HO (NF-HO and F-HO) were monitored over 12 weeks of storage in transparent glass bottles. F-HO showed a better hydrolytic and oxidative status than NF-HO during storage. As a result, F-HO also displayed better preservation of total MUFAs and PUFAs in the autoxidation process. Filtration consistently reduced chlorophylls, thus causing a variation in the natural color of HO. Accordingly, F-HO not only revealed an increased resistance to photooxidation but it was also suitable for storage in clear bottles within 12 weeks. F-HO predictably showed lower carotenoids, tocopherols, polyphenols, and squalene compared to NF-HO. However, filtration appeared to play a “protective role” toward these antioxidants, which had lower degradation rates in F-HO than NF-HO for 12 weeks. Interestingly, the element profile of HO was not affected by filtration and remained stable during the study period. Overall, this study may be of practical use to both producers and marketers of cold-pressed HO.

The Influence of the Used Bleaching Earth on the Content of Natural Dyes in Hemp (Cannabis sativa L.) Oils

“…In the case of BE3, this is due to there being too large of a disproportion between the parameters of the oils obtained in the CP and HP variants, especially considering the ratio of removed chlorophylls to carotenoids. Referring to the obtained results of the work of Lo Turco et al [45], where it was found that the reduction in natural dyes occurs at the stage of oil filtration, it can be concluded that BE4 (2.5%) has poor adsorption properties regarding carotenoid dyes. BE1, BE6, and BE7 at doses of 5.0% were the most effective at removing natural dyes (blue field in Figure 2b).…”

Assessment of the Accuracy of Nutrition Label and Chemical Composition of Plant-Based Milks Available on the Italian Market

“…For the extraction of tocopherols, 2 g of each freeze-dried PBM was mixed with 4 mL of n-hexane in a dark tube, stirred, and added with further 2 mL of methanolic KOH. Then, the mixture was stirred and centrifuged for 10 min at 4000× g at 4 • C. The supernatant was filtered through a 0.2 µm nylon filter, transferred into an amber vial, and analyzed by high-performance liquid chromatography coupled to a fluorescence detector (HPLC-FD) (Shimadzu, Milan, Italy) according to a protocol already proposed by Lo Turco and colleagues [31]. A LiChrosorb Si 60 (5 µm) column (4.6 mm I.D.…”

Effects of Centrifugation on the Oxidative Stability and Antioxidant Profile of Cold-Pressed Rapeseed Oil during Storage

“…The results of the analysis of the content of pigments and polyphenols are included in Table 2. Chlorophyll has a dual role: in daylight, it can act as a pro-oxidant causing oxidative instability, color change, and generally diminishing the nutritional attributes of the oil, but on the other hand, it can also act as an antioxidant agent in the dark [38,39]. The content of chlorophyll in oils can be very diverse and depends on the degree of maturity of the seeds, harvesting conditions, and also depends on conditions of drying and storage.…”