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1、丁瀘平博士中国齐鲁工业大学客座教授美国酒花种植协会代表哈普丁啤酒花咨询米勒库尔斯啤酒公司退休Dr.PatrickTingAdjunctProfessor,QiluUniversityofTechnologyHopGrowersofAmericaHopTingResources,LLCMillerCoors(retired)啤酒花香味和苦味的科学背景Sciencebehindhoparomaandbitternessinbeer酒花苦味香气和风味分子的演变Moleculartransformationofhopbi
2、ttering,aromaandflavorHORHOOHOOOSHOSHOHOHSH啤酒花分子如何进入啤酒?howthehopmoleculesfindtheirwayintobeer苦味(bitterness)-酒花软树脂部分(softresin)衍生的分子酒花香味(hoppy)-香油化合物衍生的分子(hopoil),酒花品种(variety),添加时间(additiontime),添加量(quantity)酵母代谢(yeastmetabolisms):酯(esters),醇(alcohols),酸(acid
3、s),含硫物质(sulfur),萜烯类,萜烯醇化合物(terpenoids)苦味(bitterness)•酿造过程中α-酸被转化为更水溶性的异α-酸(isomerization)•量化异-α-酸和啤酒的苦味(IBUandiso-a-acids)抗微生物(antimicrobial)泡沫(foam)顺式(cis)异a-酸ROHOOHOHOROOOHOH+ROOOHOHOH反式(trans)异a-酸a-酸O异-α-酸的三个缺点(Threedefaultsofiso-a-acids)对光不稳定(lightunstabl
4、e)风味不稳定,易氧化(susceptibletooxidation)化学性质不稳定(chemicalunstable)对光不稳定-紫外线和可见光(由核黄素活化)lightinstability-UVandVisiblelight(riboflavin)琥珀色透明绿色OORHOOHOhvSH-SH臭鼬或日光臭(1954-1962)三甲烷基二丁烯一硫(3M2B1T)阈值2-4ppt(ng/L,10-12mg/L)S-S-SCH3S-S-CH33M2B-methyldisulfide3M2B-methyltrisul
5、fideL.Lusket.al(2009)风味不稳定,易氧化和分解(susceptibletooxidationanddegradation)OORHOOHOORHOOHOHOCOH+O2奶酪和臭袜子的气味cheesyanddirtysocksodors损失苦味lossbitterness化学性质不稳定(chemicalinstability)合异α-酸正异α-酸1985MillerBrewingCo.顺式反式反式顺式2014ChristinaSchmidt,alet.啤酒贮藏期间酒花苦酸转化和口感shelf-l
6、ifeofiso-a-acids反式异-α-酸经非氧化,酸性催化环化反应,产生苦涩味的三和四环化合物积累于啤酒中。Aciditycatalyzesthecyclizationoftrans-iso-a-acidstotriandtetra-cycliciso-a-acidsderivativesandresultsinharshandstringentbitternessinbeer.DanielIntelmannet.Al.J.Agric.FoodChem.,2011,59(5),pp1939–1953顺式异a
7、-酸ROHOOHOHOROOOHOH+ROOOHOHOH反式异a-酸a-酸OH+/无氧ChristinaSchmidt,MartinBiendl,AnnikaLagemann,GeorgStettner,ChristianVogt,AndreasDunkel,andThomasHofmann,J.Am.Soc.Brew.Chem.72(2):116-125,2014苦+涩高压液相色谱分析啤酒四氢异-a-酸成分(HPLCoftertrahydroisoafter7month24°Cstorage)BarbaraJa
8、skula,EvelienSyryn,KoenGoiris,GertDeRouck,FilipVanOpstaele,JessikaDeClippeleer,J.Am.Soc.Brew.Chem.65(1):38-46,2007四氢异a-酸啤酒tetrahydroiso二氢异a-酸啤酒dihydroiso强制老化(forcedaging)条件40°CRHOOHOOO四氢异