Control Technology Of Sediment On The Surface Of Salted Chinese Olive

Chinese olives[Canarium album(Lour.)Raeusch],a Chinese southern special fruit,most varieties of them taste bit and just can be processed into Chinese olive preserves.According to GB2760-2007,alum can not be used for processing preserves.The surface of Chinese olive will form a layer offwhite sediment during the salting process,and it will drag into the final products of Chinese olive preserves,which seriously affect the exterior quality of products and desire of consumers to purchase.In order to solve this technical problems,this paper studies the physicochemical property,main components and the formation mechanism of White Sediment on the Surface of Salted Chinese Olive(WS SCO),then developing the WSSCO controlling technology.The main results were as follows:(1)Study on physical chemical properties and main components of WSSCOTo study the physical chemical properties and main components,using the vacuum dry WSSCO as the object.Solubility of WSSCO were studied,the results showed that it is insoluble in water and acid(except for nitric acid),but soluble in alkali and a variety of organic solvents.The content of mineral elements that forming insoluble salt in WSSCO was very low(less than 0.08%),which was measured by ICP-MS.Therefore,we can determine that the main component of WSSCO is not insoluble salt.The content of C、N in WSSCO is(51.75±1.19)%、(1.46±0.07)%respectively,measured by element analysis method.According to the protein nitrogen mass fraction conversion the protein content is(9.125±0.437)%.Finally,the content of polyphenols determined by Folin-phenol reagent method and ash of WSSCO are high,respectively(30.81±0.61)%and(4.5±0.12)%.Therefore,we can determine the main component of WSSCO is dissociative polyphenols,protein and ash(sum is 44.4%),and the other main component is insoluble polyphenol protein complexes,combining with the Insolubility and carbon element content.(2)Study on the formation mechanism of WSSCOPractical experience shows that the formation of WSSCO is related to the Chinese olive varieties and salting conditions,so this paper study the formation mechanism of the WSSCO from the two aspects.The results shows that there are little difference of the main components and mineral element between ’Raoping’ which easiest forms sediment,’Huiyuan’ and ’Changying’,but the polyphenol and soluble protein content are the highest and especially the polyphenol content on peel of’Raoping’ is(2.675±0.035)%(wet weight).There is a obvious negative correlation between WSSCO and polyphenol and soluble protein content of the salt olive(Significant degree are respectively-0.967 and-0.950).Therefore,polyphenols and soluble protein are the precursors of WSSCO.Studying the effect of salting conditions on the formation of WSSCO by turbidity meter.H+can change the hydrophobic of protein to effect the combination protein and polyphenols.When salt solution pH is 2.25～2.50,WSSCO produces least.Because the high concentration salt reduce the protein solubility and sodium metabisulfite can protect polyphenols and destroy protein structure,preventing them combination,when salt and sodium metabisulfite concentration increase,the WSSCO content would descend.The high concentration of Ca2+can complex with phenolic hydroxyl forming insoluble compounds.When the Ca2+ concentration is below 0.25%(w/v),there is no effect on WSSCO,while the concentration more than 0.25%(w/v),it can promote the formation of WSSCO.This suggests that regulating saline conditions can inhibit the formation of WSSCO,having a certain application value to explore the best technology of controlling WSSCO forming.(3)Study on the control technology of WSSCOThis study focused on the effect of salting method controlling WSSCO by using the cheap and the most commonly Raoping as the research object.Based on the single factor experiment,the content of Sodium sulfite,citric acid and the calcium chloride were optimized.Turbidity and sensory evaluation were investigated using orthogonal experiment to obtain optimal salting condition.Sequence of factors that affect the turbidity(100NTU equivalent to 1.00mg WSSCO(dry weight))and sensory score of the salt Chinese olive was Sodium sulfite>citric acid>calcium chloride.Based on the results,the best salting condition for salt Chinese olive was determined with 1.50%of sodium sulfite,0.4%of citric acid,0.25%of calcium chloride and 17.78%of sodium chloride.The salted Chinese olive obtained by following these conditions showed uniform yellow color,full particles without shrinking and good quality.