Bleaching is a necessary step in the production of refined camellia oil (Camellia oleifera Abel) since crude oil has a dark brown color, due to pigments extracted from the seed coat during pressing, which is unacceptable to consumers. In order to understand the quality change and oxidative state of camellia oil in the bleaching step, measurements of various quality parameters, i.e. peroxide value (POV), free fatty acids (FFA), UV absorbance, and the volatile profiles of crude and bleached oils, were carried out. The results showed that FFA, K 270 , and K 232 increased, whereas POV decreased, with increase of the activated earth dosage of 0-4% and of bleaching time from 0 to 40 min at 110 7C. As the amount of activated earth was increased from 0 to 4% with bleaching at 110 7C for 30 min, various classes of volatile compounds increased in concentration: aldehydes (23.7 mg/g), alcohols (13.2 mg/g), esters (8.0 mg/g), alkenes (2.0 mg/g) and ketones (1.9 mg/g). Likewise, when bleaching was carried out at 110 7C with 3% activated earth and the bleaching time varied between 0 and 40 min, the concentrations of volatile compounds also increased: aldehydes (27.7 mg/g), alcohols (18.2 mg/g), esters (7.3 mg/g), ketones (3.2 mg/g) and alkenes (0.6 mg/g). These findings indicate that hydroperoxides in the oil were decomposed into lower-molecular-weight products in the process of bleaching and that the extent of this decomposition can be controlled by time and amount of activated earth.

A novel acrylated poly(ethylene glycol)-co-poly(xylitol sebacate) (PEXS-A) hydrogel for 3D printing ink and cell encapsulation for tissue engineering application.

Apricot kernels were roasted at various temperatures (120-180 C) for 10 min and changes in the fattyacid profiles, oxidative stability, and antioxidant activity, as well as the total phenolic contents (TPC) of the oils and skin (seed coat), were monitored. Roasting has no obvious influence on profiles and contents of fatty acid, induction period (IP), browning index, TPC, and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid), (ABTS) and Oxygen Radical Absorbance Capacity (ORAC) of oils obtained from apricot naked-kernel, but increases IP, TPC, and oxidative stability in oils obtained from apricot kernel with skin. All results in the present work demonstrated that thermal treatment accelerated the production and transference of alcohol-soluble phenolics into the oil, and improved the oil oxidative stability. It is not Maillard reaction products but alcohol-soluble phenolic compounds in skins that play a role in improving the oxidative stability and antioxidant activity of oils, and inhibition for primary peroxide production was more effective than secondary peroxide production at a low roasting temperature and a short roasting time. The present findings can advance knowledge on the conditions used for utilization of coproducts (skin) of apricot kernel and facilitate large-scale production of stable oil against oxidation.

We aimed to investigate the pro-oxidant activity of polar compounds in deep-frying camellia seed oil (CO) using the accelerated oxidation test, and also to analyze the fractions and distribution of its polar compounds using high performance size exclusion chromatography (HPSEC). Our results indicated that the addition of previously isolated polar compounds to four types of CO (purified refined, unpurified refined, purified crude, and unpurified crude) reduced the oxidation induction time, which suggested that these compounds were actively prooxidant. This result is critical for the safe storage of refined oil, and for the quality monitoring of frying oil. Our HPSEC analysis showed that used CO contained polar compounds (TGO, TGD, ox-TGM, DG, and FFA). After 40 h of deep frying, the polymerization products (TGO and TGD), oxidative products (ox-TGM), and hydrolytic products (DG and FFA) comprised 54.63%, 33.54%, and 15.14% of the total polar content, respectively, suggesting that the hydrolysis reaction during the deep frying was weak compared to thermal oxidation polymerization. Based on this result, in combination with our measurement of the concentration of total polar compounds (TPC, 27%) and triacylglycerol polymers (TGP, 10-16%), we postulate that the frying life of CO is 32 h.

A thermal oxidation test of Camellia seed oil (CO) was carried out at 120°C and 180°C by Rancimat instrument. The effects of temperature on the stability of CO were evaluated by measuring various chemical properties as well as the composition of nonpolar and polar triglycerides. The results showed that the rate of TAG degradation from CO during the first hour at 180°C was 4.16 times higher than at 120°C, and the formation of PTAG and TPC were 18.6 times and 8.15 times higher than at 120°C, respectively. This suggests that higher reaction temperature results in higher degree of degradation. The polymerization products (TGO and TGD), oxidation products (ox-TGM) and hydrolysates (DG and FFA) from CO were 27.67%, 59.05%, 13.32%, 66.15%, 29.28% and 5.21% after 10 hours oxidation at 120°C and 180°C, respectively, indicating that the reaction process of CO at the two temperatures was very different. The polymerization reaction was dominant at 180°C, while the oxidation reaction was the dominant reaction at 120°C. The degree of hydrolysis at 120°C was higher than at 180°C. In addition, polar compounds TGO and TGD are considered biologically toxic and cytotoxic, and, as temperature increases, the nutritional and safety characteristics of CO worsen. Therefore, the cooking temperature of CO should not be too high.