WJEC Level 3 Diploma In Food Science And Nutrition
47 The properties of foods and how they are changed ,Q IRRG VFLHQFH IRRGV DUH GHVFULEHG DV KDYLQJ SK\VLFDO FKHPLFDO DQG IXQFWLRQDO properties . 3URSHUWLHV DUH WKH FKDUDFWHULVWLFV RI IRRGV WKDW FDQ HLWKHU EH PHDVXUHG RU REVHUYHG ⦁ Physical SURSHUWLHV RI IRRGV LQFOXGH WKHLU WH[WXUH VKDSH FRORXU DURPD VPHOO PHOWLQJ ERLOLQJ DQG IUHH]LQJ SRLQW ⦁ Chemical properties are the chemical reactions that take place in foods when they DUH VWRUHG SURFHVVHG SUHSDUHG PL[HG ZLWK RWKHU IRRGV FRRNHG RU FKLOOHG H J ZKDW KDSSHQV ZKHQ DQ HJJ LV ERLOHG LQ ZDWHU RU D UDZ FDNH PL[WXUH LV EDNHG RU OHPRQ MXLFH LV PL[HG ZLWK FUHDP RU PHDW LV URDVWHG RU VWHZHG ⦁ Functional SURSHUWLHV RI IRRGV GHVFULEH ZKDW D IRRG ZLOO GR ZKHQ GLʏHUHQW SURFHVVHV H J PL[LQJ KHDWLQJ FRROLQJ ZKLVNLQJ DUH DSSOLHG WR LW H J VSUHDG PHOW VHW EHFRPH SOLDEOH FU\VWDOOLVH VRIWHQ KDUGHQ WRXJKHQ WUDS DLU HPXOVLI\ EHFRPH EULWWOH HWF 7KH SURSHUWLHV RI IRRGV FDQ EH FKDQJHG E\ D QXPEHU RI GLʏHUHQW variables $ YDULDEOH LV DQ\ IDFWRU LQ DQ H[SHULPHQW WKDW FDQ EH PDQLSXODWHG DOWHUHG RU PHDVXUHG H J LQ D IRRG H[SHULPHQW WKH YDULDEOHV PLJKW EH WHPSHUDWXUH S+ FRRNLQJ WLPH FRRNLQJ PHWKRG PHFKDQLFDO DJLWDWLRQ ZKLVNLQJ EHDWLQJ HWF TXDQWLWLHV SURSRUWLRQV RI LQJUHGLHQWV HWF .QRZOHGJH RI WKHVH SURSHUWLHV LV LPSRUWDQW IRU XQGHUVWDQGLQJ KRZ WKH\ LQflXHQFH IRRG SURGXFWLRQ ZKLFK WKH UHVW RI WKLV FKDSWHU H[SODLQV Denaturation 7R GHQDWXUH VRPHWKLQJ PHDQV WR FKDQJH LW ,Q IRRG VFLHQFH denaturation applies mainly to proteins . ,Q ELRFKHPLVWU\ WHUPV SURWHLQV DUH YHU\ ODUJH PROHFXOHV DQG WKHLU SURSHUWLHV are controlled by the sequence of their amino acids which is unique to each protein. $PLQR DFLGV DUH MRLQHG WR RQH DQRWKHU E\ peptide bonds DQG IRUP ORQJ SRO\SHSWLGH chains which make up protein molecules: 7KH VWUXFWXUH RI SURWHLQ PROHFXOHV LV VKDSHG E\ D IRXU VWDJH IROGLQJ VHTXHQFH RI WKH polypeptide chains $V WKH SRO\SHSWLGH FKDLQV IROG WKH VLGH FKDLQV JURXSV RQ GLʏHUHQW DPLQR DFLGV R in WKH HTXDWLRQ DERYH FRPH FORVH WR HDFK RWKHU DQG IRUP GLʏHUHQW W\SHV RI bonds H J hydrogen bonds and disulphide (sulphur to sulphur) bridges ). AC1.1 AC1.2 Denaturation – the unfolding of a compact protein molecule due to the breaking of some of the bonds that hold it together Properties – the characteristics of foods that can either be measured or observed Variable – any factor in an experiment that can be manipulated, altered or measured Key terms C N 2 H O O R C C NH 2 H OH O R C C NH 2 H OH O R C C NH 2 H OH O R C C NH 2 H OH O R C + C NH 2 H OH O R C C NH 2 H OH O R C + + C NH 2 H H O O R C CN H H H OH O R C water peptide bond + C NH 2 H H O O R C CN H H H OH O R C water peptide bond Condensation reaction between two amino acids bonds 2nd stage - either coiled or folded 3rd stage 1st stage The properties of foods and how they are changed
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