| Raspberry, a kind of polymerization berry fruit which belongs to rosefamily(Rubus idaeus L). The ripe one is dark red, tender and juicy. It is rich in variousamino acids, vitamins, mineral substances， micro-elements, and other uniquefunctional ingredients, such as polyphenols, anthocyanin, gallogen, raspberry ketone,superoxide dismutase (SOD), salicylic acid and etc. The Raspberry was known as the"GoldenFruit" and "the third-generation fruit " for its content of vitamin E and SODwhich is highest in all kinds of fruits.Raspberry is suited to process raspberry wine, juice and pigment for its highcontent of sugar, organic acid, anthocyanin and high juice yield. Raspberry wine ismild of non-food-type, which can adjust the physiological equilibrium of people andbenefits for health as a result of long-term drink. Based on previous study of thisresearch group, further relevant studies were carried out to explore the law of thevariation of each parameter during the processing and to produce high quality fruitwine. The study subjects here as follows:(1)The nutrition constituent of raspberryfruit was analyzed.(2) A High Performance Liquid Chromatography (HPLC) methodwas established for detection of ellagic acid in rasberry.(3) Studies on the dynamicchanges of various components during the fermentation process，mainly on total acid,total sugar, soluble solids, pH, polyphenols, tannins, anthocyanins, organic acids andellagic acid. The aroma components were also detected.(4) The technology ofraspberry wine clearing and excess acid removing was studied. Main researchfindings of this study as follows:1.The major nutrition constituents analysis of raspberry fruit. The major nutritionconstituents of raspberry fruit are: moisture of82.65%,1.6164g/100g of fat,1.052g/100g of protein,16.6mg/100g of vitamin C,63.38g/L of sugar,72.5g/L of totalsugar,10.25%of soluble solids,18.67g/L of total acid,2.92of pH,0.077g/L ofvolatile acid,378.38mg/L of cyanin,0.34g/L of polyphenols,4.08g/L of tannins.2.A High Performance Liquid Chromatography (HPLC) method for detection ofellagic acid in raspberry juice was established. The mobile phase was a mixture ofphosphte buffer (5%), methanol and ethyl-acetate (pH2.7), the volume ratio of44:2:54. Flow rate was0.6mL/min;0-6min with ultraviolet detector at a wavelengthof400nm, then the wavelength was transformed to350nm in6-7.5min, at last in7.5-30min wavelength was adjusted downward to254nm. The results showed thatthe method was suitable for the determination of ellagic acid in raspberry juice. Average recovery at raspberry juice was99.08%and the relative standard deviations were0.077%.The method was simple, accurate, free of impurities interference and good separation.The mothed was utilized in the determination of ellagic acid in blackberry juicewithout going through a complex pre-treatment.3.The dynamic changes of various components during the fermentation process.Saccharomyces cerevisiae was applied in the fermentation. After9daysmainfermentation at22℃, the raspberry juice was siphoned to be stored at16℃for180days ageing. The variation of major nutrition constituents was tracked and testedfor the mean time. The results indicated that, the total sugar content decreased from200g/L to5g/L around. The total acid varied in little range from14.5g/L to14.7g/Lduring the main fermentation, while droped to10.8g/L in Maturation period. Similarly,pH Value varied in little range from3.5to3.45during the main fermentation, whiledroped to3.35during aging. The tannins content ascended from4.5g/L to5.5g/Lduring the main fermentation, while decreased slightly in maturation period andstabilized around5.48g/L for180days ageing. The total phenols content decreasedslightly from1.15g/L to0.915g/L during the main fermentation, and stabilized around0.886g/L for180days ageing. The anthocyanin content decreased sharply from258.77g/L to109.85g/L in first two days of the main fermentation, while the declineslowed three days later and fell to45.89g/L at the end of main fermentation. Duringthe maturation period, the anthocyanin content decreased slightly and stabilizedaround28.6g/L for180days ageing.The organic acid varied little during the mainfermentation, while droped slightly in maturation period. The ellagic acid content roseto51.31g/L in first three days of the main fermentation, while droped sharply threedays later, and varied little in maturation period.4.Preliminary study on raspberry wine clearing and excess acid removing. In thisstudy, bentonite, PVPP, gelatin and pectinase were applied in clearing the raspberrywine, and resins were used in removing excess organic acid. The results indicate that,the clearing effects is significant by adding1.25g gelatin to1liter of wine, and theorganic acid content decreases from13.88g/L to10.8g/L by using the resin of typeD311with3mL/min of flow. As a result, the clearing and tart removing processimprove the quality of raspberry wine. |
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