Qiuyu Xia

Chemical composition changes of post-harvest coconut inflorescence sap during natural fermentation

Coconut inflorescence sap (CIS) is sweet, oyster-white and translucent and was reported to be highly nutritive and a good digestive agent. The chemical composition changes including total sugar, reducing sugar, ethanol, total acidity, volatile acid, amino acid, vitamin C and total phenolic contents of postharvest coconut inflorescence sap (PCIS) were investigated during a 12-day natural fermentation, and the variety and content of phenolic compounds of fresh coconut inflorescence sap (FCIS) and natural fermented coconut inflorescence sap (NCIS) were also studied by an high performance liquid chromatography (HPLC) system. Total acid, volatile acid and total phenolic contents increased during natural fermentation, while total sugar contents decreased during natural fermentation. The amino acid content declined steadily after harvesting until 3 days, but then remained almost constant. Vitamin C content decreased on day 1, slowly rose to 20.7 mg/L on day 3, and then decreased obviously. Five kinds of phenolic compounds were detected by HPLC. These compounds all increased in NCIS compared with FCIS; both NCIS and FCIS also contained other kinds of phenolic compounds.

Lipase-catalyzed synthesis of conjugated linoleyl β-sitosterol and its cholesterol-lowering properties in mice.

Conjugated linoleyl beta-sitosterol (CLS) was prepared from beta-sitosterol and conjugated linoleic acid (CLA) via lipase-catalyzed synthesis in n-hexane in the presence of molecular sieves. Its plasma cholesterol-lowering properties were also studied. The optimal biosynthesis conditions were as follows: beta-sitosterol concentration of 50 micromol/mL, the molar ratio of CLA to beta-sitosterol of 1:1, the lipase concentration of 20 mg/mL, and 4 A molecular sieve concentration of 60 mg/mL in n-hexane at 50 degrees C with vigorous shaking of 150 rpm for 72 h, and the highest yield of CLS reached 72.6%. The isolated CLS mixed with mice feed had good cholesterol-lowering properties. It decreased serum total cholesterol (TC), serum triacylglycerols (TAGs), serum low-density lipoprotein cholesterol (LDL-C), atherogenic index (AI), liver weight (LW), liver index (LI), liver TC, and TAGs of mice, which was shown that CLS could prevent the formation of atherosclerosis and moderate the fat pathologic changes of liver. However, the HDL-C was not decreased, which proved the advantage of CLS over the other cholesterol-lowering products.

Chemical composition of Chinese palm fruit and chemical properties of the oil extracts

The proximate composition, mineral concentration of fleshy mesocarp, palm meat (PM) and palm kernel (PK) of oil palm fruit ( Elaeis guineensis S.L.Dura ) produced in Hainan, China were investigated. The fatty acid composition, chemical properties and minor constituents of palm oil (PO) and palm kernel oil (PKO) were also studied. The crude fat of PM and PK were 68.09±3.57% and 49.36±2.61%, respectively. The PM and PK were found to be good sources of minerals. The acid value (AV) and free fatty acid (FFA) of PO extracted from fresh PM were much higher. If the fresh PM were heated at 100oC for 30 min, the AV and % FFA could be reduced to 4.62±0.04 mgKOH/g and 2.72±0.002%, respectively. The major fatty acid of PO was palmitic acid 39.93±1.66% and that of PKO was lauric acid 48.01±0.69%. Tocopherol isomer (α-, (β+γ)- and δ-) contents in PO were 68.8±1.84, 22.8±0.54 and 11.8±0.12 mg/kg, respectively. The β-carotene content in PO was 901.5±11.95 mg/kg. The content of sterols in PO and PKO were 880.0±5.23 and 858.0±4.37 mg/kg, respectively. PO and PKO exhibited good chemical properties and could be used as edible oils and for industrial applications. There are almost no data about Chinese palm fruit now and this study systematically researched on it, which can provide useful information for Chinese oil palm industry. Key words: Chemical composition, palm fruit, palm oil, palm kernel oil, chemical properties.