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EFFECT OF SUPERHEATED STEAM HEATING ONFAT RELATED CHANGES IN RECONSTITUTE MILKAND FRESH MILKGHAZWAN MAHDY SALIHUNIVERSITI SAINS MALAYSIA2016

EFFECT OF SUPERHEATED STEAM HEATING ONFAT RELATED CHANGES IN RECONSTITUTE MILKAND FRESH MILKByGhazwan Mahdy SalihThesis submitted in fulfillment of therequirements for the degree ofDoctor of philosophyApril 2016

ACKNOWLEDGEMENTFirst and foremost, I praised the Al-Mighty Allah, for the strength and guidanceenabling me to accomplish this research study and all tasks that we are given to me. Iwould like to express my sincere gratitude to my supervisor Dr. Tajul A.Yang for thecounties supporting of my Ph.D study and research for his patience, advices,enthusiasm, and immense knowledge. His guidance helps me in all the time of mystudy and writing this thesis.I would like to make this opportunity to express my deepest appreciation to the Deanand staff of food technology division, school of industrial technology, USM. Also, Ipleased to thank my friends in USM for their warm friendship, support and advicesduring my study.My deepest and most heartfelt gratitude to my family, my father and my mother witha special thanks to my second half my waif (Allahen. H) for support, give me hopeand strength. Also I would thanks my brothers and all friends for them prayer,supporting and encouragement to me.Last but defiantly not least, I would like to thank my scholarship supporting from mycountry especially the (ministry of higher education of Iraq) and my University(University of Tikrit) and all my lecturers in Agriculture College, Food Science andTechnology. My appreciation to all.Ghazwan Mahdy SalihApril 2016ii

TABLE OF CONTENTSpageACNOWLEDGMENTiiTABLE OF CONTENTSiiiLIST OF TABLESxvLIST OF FIGURESxxiiLIST OF SYMBOLS/ ABBREVIATIONxxxvABSTRAKxxxviiABSTRACTxxxixCHAPTER 1: GENERAL INTRODUCTION11.1 Background information11.2 Problem statement51.3 Objective6CHAPTER 2: LITERATURE REVIEW2.1 Cow’s milk72.1.1 Cow’s milk history72.1.2 Milk composition72.1.3 Milk fat9122.2. The heating operation2.2.1 Milk heat fat operation122.2.2 Chemistry of thermal processing12iii

162.3 Oxidative reaction2.3.1 Oxidative reaction162.3.2 Hydroperoxides decomposition and formation off-20flavour compounds232.4 Main factors affecting fat oxidation2.4.1 Oxygen232.4.2 Temperature242.4.3 Metal types252.4.4 Lipid composition262.4.5 Antioxidants272.5 Measuring Oxidative Stability of Milk292.5.1 Peroxide value (PV)302.5.2 Thiobarbituric Acid (TBA) Test312.5.3 p -Anisidine Value (p -AnV)322.5.4 Gas Chromatography332.5.5 Total Antioxidant Capacity (TAC)352.5.6 Totox value362.5.7 Acid value372.6 Superheated steam process392.6.1 Superheated steam392.6.2 Mechanism of superheated steam392.6.3 Superheated steam energy saving412.6.4 Safety and environmental friendly with superheated43steam2.6.5 Application of superheated steam with food processingiv43

industry2.6.6 Application of superheated steam with non-food45technologyCHAPTER 3: EFFECT OF SUPERHEATED STEAMTREATMENT ON THE PHYSICAL PROPERTIES, LIPIDSTABILITY, VITAMINS, ANTIOXIDANT ACTIVITY ANDVOLATILECOMPOUNDSOFRECONSTITUTEDWHOLE MILK POWDER3.1 Introduction463.2 Materials and Methods503.2.1 Whole milk powder503.2.2 Whole milk powder reconstitution503.2.3 Heating reconstituted milk powder by superheated50steam oven3.2.4 Colour measurement513.2.5 Viscosity and density measurement513.2.6 pH measurement513.2.7 Fat extraction513.2.8 Peroxide value (PV)523.2.9 Acid value523.2.10 TBARS test533.2.11 p-Anisidine value test533.2.12 Totox value543.2.13 Fatty acids methyl ester54v

3.2.14 GC-FID analysis of fatty acids543.2.15 Identify of fatty acid553.2.16 Fat- soluble vitamins (retinol and α-tocopherol)553.2.17 Water- soluble vitamins (ascorbic acid)563.2.18 Preparation of standard solutions563.2.19 HPLC conditions of Water soluble vitamin (ascorbic56acid)3.2.20 HPLC condition of fat soluble vitamins (retinol and α-57tocopherol)3.2.21 Scavenging effect of DPPH radicals573.2.22Volatile compounds analysis by SPME–GCMS583.2.23 Statistical analysis58593.3 Results and Discussion3.3.1 Colour analysis593.3.2 Viscosity and density613.3.3 Effect of SHS heat treatment on the oxidation milk fat,63acid value and pH3.3.4 Peroxide value643.3.5 TBARS value663.3.6 p-Anisidine Value673.3.7 Totox value683.3.8 pH value693.3.9 Effect of superheated steam (time and temperature) on71fatty acids composition of reconstituted whole milkpowdervi

3.3.9.a Effect SHS on saturated fatty acids (SFA)713.3.9.b Effect of superheated steam (time and temperature) on84MUFA composition3.3.9.c Effect of superheated steam (time and temperature) on86PUFA composition3.3.9.d Effect superheated steam heat treatment on formation88Trans fatty acids in reconstituted whole milk powder.3.3.10 Effect superheated steam temperature and time onvitamins and antioxidant activity in91reconstructedwhole milk powder3.3.11 Volatile compounds of reconstituted whole milk95powder1013.4 ConclusionCHAPTER 4: EFFECT OF SUPERHEATED STEAM HEATTREATMENT ON THE PHYSICAL PROPERTTIES, LIPIDSTABILITY, VITAMINS, ANTIOXIDANT ACTIVITY ANDVOLATILECOMPOUNDSOFRECONSTITUTEDOMEGA 3&6 PLUS MILK POWDER4.1 Introduction1044.2 Materials and Methods1074.2.1 Omega- 3&6 plus milk powder1074.2.2 Omega- 3&6 plus milk powder reconstitution1074.2.3 Heating of omega-3&6 reconstituted milk powder by107vii

superheated steam oven4.2.4 Colour measurement1074.2.5 Viscosity and density measurement1084.2.6 Fat extraction1084.2.7 Peroxide oxidation value1084.2.8 Acid value1084.2.9 TBARS test1084.2.10 p-Anisidine value test1084.2.11 Totox value1094.2.12 pH value1094.2.13 Fatty acids methyl ester1094.2.14 GC-FID analysis of fatty acids1094.2.15 Identify of fatty acid1094.2.16 Fat- soluble vitamins (retinol and α-tocopherol)1104.2.17 Water- soluble vitamins (ascorbic acid)1104.2.18 Preparation of standard solutions1104.2.19 HPLC conditions of Water soluble vitamin (ascorbic111acid)4.2.20 HPLC condition of fat soluble vitamins (retinol and111α-tocopherol)4.2.21 Scavenging effect of DPPH radicals1114.2.22 Volatile compounds analysis by SPME–GCMS1124.2.23 Statistical analysis1121124.3 Results and Discussion4.3.1 Colour analysis112viii

4.3.2 Viscosity and density1154.3.3 Effect superheated steam on Lipid Oxidation of118reconstituted omega- 3&6 plus milk4.3.3.a Acid value1184.3.3.b Peroxide value1194.3.3.c TBARS value1204.3.3.d P-Anisidine value1204.3.3.e Totox value1224.3.3.f pH value1234.3.4 Effects of superheated steam (time and temperature) on124fatty acids composition of reconstituted omega-3&6plus milk powder4.3.5 Effect superheated steam heat treatment on formation133Trans fatty acids in reconstituted omega- 3&6 plus milkpowder4.3.6 Effect superheated steam temperature and time on135vitamins and antioxidant activity in reconstructedomega-3&6 plus milk powder4.3.7 Volatile compounds of reconstituted omega3-6 plus140milk powder1454.4 ConclusionCHAPTER 5: EFFECT OF SUPERHEATED STEAM HEATTREATMENT ON THE PHYSICAL PROPERTTIES, LIPIDSTABILITY, ANTIOXIDANT ACTIVITY AND VOLATILEix

COMPOUNDS OF RAW MILK5.1 Introduction1465.2 Materials and Methods1485.2.1 Raw milk collocation1485.2.2 Heated raw milk by superheated steam oven1485.2.3 Colour measurement1485.2.4 Viscosity and density measurement1495.2.5 Fat extraction1495.2.6 Peroxide oxidation value1495.2.7 Acid value1495.2.8 TBARS test1495.2.9 p-Anisidine value test1495.2.10 Totox value1505.2.11 pH value1505.2.12 Fatty acids methyl ester1505.2.13 GC-FID analysis of fatty acids1505.2.14 Identification of fatty acids1505.2.15 Scavenging effect of DPPH radicals1515.2.16 Volatile compounds analysis by SPME–GCMS1515.2.17 Microbiological analysis1515.2.17.a Total bacteria count1515.2.17.b Total coliform count1515.2.17.c Staphylococci aureus1525.2.18 Statistical analysis1521525.3 Results and Discussionx

5.3.1 Colour analysis1525.3.2 viscosity and density1555.3.3 Effect of superheated steam heat treatment on the157oxidation milk fat, acid value and pH of raw milk5.3.4 Peroxide value (PV)1595.3.5 TBARS value1605.3.6 P-Anisidine value1625.3.7 Totox value1635.3.8 pH value1645.3.9 Effects of superheated steam (time and temperature) on165fatty acids composition of raw milk5.3.10 Effect superheated steam temperature and time on170antioxidant activity in raw milk5.3.11 Effect superheated steam on total bacteria count,172coliform count and Staphylococcus aureus of raw milk5.3.12 Volatile compounds of raw milk heated by SHS1741805.4 ConclusionCHAPTER 6: APPLICATION OF RESPONSE TINGSUBJECTEDTOSUPERHEATED STEAM TREATMENTS IN RELEVANCETO ANTIOXIDANT AND LIPID OXIDATION6.1 Introduction1826.2 Materials and Methods185xi

6.2.1 Raw milk sample1856.2.2 Experimental Design for Optimization1866.2.3 Heating raw milk by superheated steam oven1876.2.4 Peroxide value1886.2.5 p-Anisidine test1896.2.6 TBARS test1896.2.7 Scavenging effect of DPPH radicals1906.2.8 Total bacteria count1901906.3 Results and Discussion6.3.1 Analysis of Response Surfaces1956.3.2 Optimization of heating conditions2022026.4 ConclusionsCHAPTER 7: EFFECT OF SUPERHEATED STEAM,MICROWAVE AND CONVENTIONAL HEATED ONPHYSICOCHEMICAL,MICROBIOLOGICAL,LIPIDOXIDATION, VITAMINS, ANTIOXIDANT ACTIVITY,AND VOLATILE COMPOUNDS OF RAW MILK7.1 Introduction2047.2 Materials and Methods2077.2.1 Raw milk collocation2077.2.2 Heat raw milk by SHS, microwave and convention207methods7.2.3 Colour measurement2087.2.4 Viscosity and density measurement208xii

7.2.5 Fat extraction2087.2.6 Peroxide value2087.2.7 Acid value2097.2.8 TBARS test2097.2.9 p-Anisidine value test2097.2.10 Scavenging effect of DPPH radicals2097.2.11 Fat and water- soluble vitamins (retinol, α-tocopherol209and ascorbic acid) measurement7.2.12 Volatile compounds analysis by SPME–GCMS2097.2.13 Microbiological analysis2107.2.13.a Total bacteria count2107.2.13.b Total coliform count2107.2.13.c Staphylococci aureus2107.2.14 Statistical analysis2102117.3 Results and Discussion7.3.1Colour and physical analysis2117.3.2 Effect of superheated steam heat treatment on acid and215lipid oxidation of raw milk heated by different methods7.3.2.a Acid value of raw milk2157.3.2.b Peroxide value (PV)2167.3.2.c TBARS value2187.3.2.d P-Anisidine value2207.3.2.e pH value2217.3.3 Effect different heat treatment on DPPH of raw milk2227.3.4 Effect superheated steam on total bacteria count,224xiii

coliform count and staphylococcus aureus of raw milk7.3.5 Changes of vitamin C (ascorbic acid), A (Retinol) and E226(α-tocopherol) of raw milk heated by different heattreatment methods7.3.6 Volatile compounds of raw milk heated by different228methods2347.4 ConclusionCHAPTER 8- OVERALL CONCLUSIONS ANDRECOMMENDATION8.1 Overall conclusions2368.2 Recommendation for further study238REFERENCES240APPENDICES263LIST OF PUBLICATION269xiv

LIST OF TABLESpageTable 2.1Changes in lipids during thermal processing15Table 2.2Characteristics of individual volatiles formed from19oxidative degradation of oils and fatsTable 2.3Possible origin of some aldehydes obtained from the22oxidation of oleic, linoleic, linolenic, and arachidonicacids.Table 3.1Effect of superheated steam on fatty acid (%) of74reconstitute whole milk powder on temperature (120) C and different holding time.Table 3.2Effect of superheated steam on fatty acid (%) of76reconstitute whole milk powder on temperature (135) C and different holding time.Table 3.3Effect of superheated steam on fatty acid (%) ofreconstitute whole milk powder on temperature (150) C and different holding time.xv78

Table 3.4Effect of superheated steam on fatty acid (%) of80reconstitute whole milk powder on temperature (165) C and different holding time.Table 3.5Effect of superheated steam on fatty acid (%) of82reconstitute whole milk powder on temperature (180) C and different holding time.Table rated fatty acids (mg.g-1) in reconstituted wholemilk powder at different temperature and holding time.Table 3.7Changes of vitamin A Retinol in reconstituted whole92milk powder treated by superheated steam heattreatment.Table 3.8Changes of vitamin C ascorbic acid in reconstituted93whole milk powder treated by superheated steam heattreatment.Table 3.9Changes of vitamin E α-Tocopherol in reconstituted93whole milk powder treated by superheated steam heattreatment.Table 3.10Volatile compounds in (µg/1000g) detected inxvi98

reconstitutedwholemilkpowdertreatedbysuperheated steam and compare with representvolatiles detectable above the sensory thresholdTable 3.11Volatile compounds in (µg/1000g) detected ed steam and compare with representvolatiles detectable above the sensory thresholdTable 4.1Effect of superheated steam on fatty acid (mg.g-1) of127reconstituted omega-3&6 plus milk powder ontemperature (120) C and different holding timeTable 4.2Effect of superheated steam on fatty acid (mg.g-1) of129reconstituted omega-3&6 plus milk powder ontemperature (150) C and different holding timeTable 4.3Effect of superheated steam on fatty acid (mg.g-1) of131reconstituted omega-3&6 plus milk powder ontemperature (180) C and different holding timeTable ted fatty acid (mg.g-1) in reconstituted omega3&6 plus milk powder at different temperature andholding timexvii134

Table 4.5Determination of vitamin A (Retinol) in reconstituted136omega-3&6 plus milk powder treated by superheatedsteam heat treatmentTable 4.6HPLC method for the determination of vitamin C in137reconstituted omega-3&6 plus milk powder treated bysuperheated steamTable 4.7HPLC method for the determination of vitamin E in138reconstituted omega-3&6 plus milk powder treated bysuperheated steamTable 4.8Volatile compounds in (µg/1000g) detected in142reconstituted omega-3&6 plus milk powder treated bysuperheated steam and compare with representvolatiles detectable above the sensory thresholdTable 4.9Volatile compounds in (µg/1000g) detected in143reconstituted omega-3&6 plus milk powder treated bysuperheated steam and compare with representvolatiles detectable above the sensory threshold.Table 5.1Changes in viscosity and density of raw milk sterilizedby SHS heat treatment at different temperature andxviii157

holding time.Table 5.2Changes in pH value of raw milk sterilized by SHS165heat treatment at different temperature and holdingtime.Table 5.3Fatty acids in (mg. g-1) of total lipids in raw milk168treated with SHS on 130 CTable 5.4Fatty acids in (mg. g-1) of total lipids in raw milk169treated with SHS on 140 CTable 5.5Fatty acids in (mg. g-1) of total lipids in raw milk170treated with SHS on 150 CTable 5.6Effect superheated steam treatment on total bacteria174count, coliform count and staphylococcus aureus ofraw milk.Table 5.7Volatile compounds in (µg/1000 g) detected in raw177milk treated by superheated steam and compare withrepresent volatiles detectable above the sensorythreshold.Table 5.8Volatile compounds in (µg/1000 g) detected in rawxix178

milk treated by superheated steam and compare withrepresent volatiles detectable above the sensorythreshold.Table 6.1Central composite experimental design for the raw187milk.Table 6.2Experimental values of PV (me.peroxide/kg), P-AV,192TBARS (μmol/g), DPPH radical scavenging activity(%), and TBC (cfu.ml-1) of raw milk.Table 6.3Analysis of variance (ANOVA) for response surface193quadratic model on pv (me.peroxide/kg), p-av, tbars(μmol/g), DPPH radical scavenging activity (%), andtbc (cfu.ml-1) of raw milk.Table 7.1Cows raw milk heat treatment.206Table 7.2Effect different heat treatment methods on inactivate226the total bacteria count (TBC), coliform count andstaphylococcus aureus of raw milkTable 7.3Volatile compounds in (µg/1000 g) detected in rawmilk treated by different methods compare withrepresent volatiles detectable above the sensoryxx231

thresholdTable 7.4Volatile compounds in (µg/1000 g) detected in rawmilk treated by different and compare with representvolatiles detectable above the sensory thresholdxxi232

LIST OF FIGURESPageFigure 2.1Milk fat globule size distribution from Danish10Holsteins and Jersey cowsFigure 2.2Milk fat globule membrane10Figure 2.3Principle events of fat during exposure to heat14Figure 2.4Oxidative reaction and representative products18Figure 2.5Formation of aldehydes, alcohols, and ketones from21the decomposition of hydroperoxidesFigure 2.6Reaction of 2-thiobarbituric acid (TBA) with31malonaldehydeFigure 2.7Principle reactions between malonaldehyde and p-33anisidine reagentFigure 2.8Basic superheated steam system40Figure 2.915 principle scheme diagram of superheated steam42systemxxii

Figure 3.1Changes in the lightness (L*) of reconstituted wholemilkpowder60during superheated steam heattreatment at different temperature and periods oftime. Wherea–cdifferent letters indicate significantdifference with the SHS time (p 0.05) andA-Cdifferent letters indicate significant difference withthe SHS temperatures (p 0.05).Figure 3.2Changes in the redness (a*) of reconstituted wholemilkpowder60during superheated steam heattreatment at different temperature and periods oftime. Wherea–cdifferent letters indicate significantdifference with the SHS time (p 0.05) andA-Cdifferent letters indicate significant difference withthe SHS temperatures (p 0.05).Figure 3.3Changes in the yellowness (b*) of reconstitutedwhole milk powder during superheated steam heattreatment at different temperature and holding time.Wherea–cdifferent letters indicate significantdifference with the SHS time (p 0.05) andA-Cdifferent letters indicate significant difference withthe SHS temperatures (p 0.05).xxiii61

Figure 3.4Changes in the viscosity and density values d steam heat treatment at differenttemperature and holding time. Wherea–cdifferentletters indicate significant difference with the SHStime (p 0.05) andA-Cdifferent letters indicatesignificant difference with the SHS temperatures (p 0.05).Figure 3.5Effect of superheated steam treatment on the acid64value of reconstituted whole milk powder atdifferent temperature and holding time.Figure 3.6Changes in PV value of reconstituted whole milk65powder treated by superheated steam at differenttemperature and holding time. Where,a–cdifferentletters indicate significant difference with the SHStime (p 0.05) andA-Cdifferent letters indicatesignificant difference with the SHS temperatures (p 0.05).Figure 3.7Changes in TBARS value of reconstituted wholemilk powder treated by superheated steam atdifferent temperature and holding.xxiv67

Figure 3.8changes in p-Anisidine value of reconstituted whole68milk powder treated by superheated steam atdifferent temperature and periods of time. Where, a–c different letters indicate significant difference withthe SHS time (p 0.05) and A-C different lettersindicate significant differencewith the SHStemperatures (p 0.05).Figure 3.9Effect superheated steam treatment on the Totox70value of reconstituted whole milk powder atdifferent temperature and holding time. Where, a–cdifferent letters indicate significant difference withthe SHS time (p 0.05) and A-C different lettersindicate significant differencewith the SHStemperatures (p 0.05).Figure 3.10Effect superheated steam treatment on the pH value70of reconstituted whole milk powder at differenttemperature and holding time. Where, a–c differentletters indicate significant difference with the SHStime (p 0.05) and A-C different letters indicatesignificant difference with the SHS temperatures (p 0.05).Figure 3.11Effect of superheated steam heat treatment on thexxv95

DPPH activity in reconstitute whole milk powder.Where, a–c different letters indicate significantdifference with the SHS time (p 0.05) and A-Cdifferent letters indicate significant difference withthe SHS temperatures (p 0.05).Figure 3.12Principal component analysis (PCA) biplot of SHS100milk volatile compounds measured using SMPE–GCMS analysis. F1 and F2 are the first and secondprincipal componentsFigure 3.13Principal component analysis (PCA) biplot of SHS100milk volatile compounds measured using SMPE–GCMS analysis. F2 and F3 are the second and thirdprincipal componentsFigure 4.1Changes in the lightness (L*) of reconstituted114omega-3&6 plus milk powder during superheatedsteam heat treatment at different temperature andholding time. Where, a–c different letters indicatesignificant difference with the SHS time (p 0.05)and A-C different letters indicate significantdifference with the SHS temperatures (p 0.05).Figure 4.2Changes in the redness (a*) of reconstitutedomega-3&6plusmilkxxvipowderduring112

superheated steam heat treatment at differenttemperature and holding time. Where, a–cdifferent letters indicate significant differencewith the SHS time (p 0.05) and A-C differentletters indicate significant difference with theSHS temperatures (p 0.05).Figure 4.3Changes in the yellowness (b*) of reconstituted115omega-3&6 plus milk powder during superheatedsteam heat treatment at different temperature andholding time. Where, a–c different letters indicatesignificant difference with the SHS time (p 0.05)and A-C different letters indicate significantdifference with the SHS temperatures (p 0.05).Figure 4.4Changes in the viscosity and density values of117reconstituted omega-3&6 plus milk powder treatedby superheated steam heat treatment at differenttemperature and holding time. Where, a–c differentletters indicate significant difference with the SHStime (p 0.05) and A-C different letters indicatesignificant difference with the SHS temperatures (p 0.05).Figure 4.5Effect of superheated steam (temperature and time)on the acid value to reconstituted omega-3&6 plusxxvii118

milk powderFigure 4.6Effect of superheated steam (temperature and time)119on the PV value to reconstitute omega-3&6 plusmilk powder. Where, a–c different letters indicatesignificant difference with the SHS time (p 0.05)and A-C different letters indicate significantdifference with the SHS temperatures (p 0.05).Figure 4.7Effect of superheated steam (temperature and time)120on the TBARS values to reconstituted omega-3&6plus milk powderFigure 4.8Effect of superheated steam (temperature and time)121on the P-Anisidine value to reconstituted omega3&6 plus milk powder.Figure 4.9Effect of superheated steam treatment on the Totoxvalue of reconstitute omega-3&6 plus milk powderat different temperature and holding time. Where, a–cdifferent letters indicate significant difference withthe SHS time (p 0.05) andA-Cindicate significant differencetemperatures (p 0.05).xxviiidifferent letterswith the SHS122

Figure 4.10Effect of superheated steam heating on the pH value123of reconstitute omega-3&6 plus milk powder.Where,a–cdifferent letters indicate significantdifference with the SHS time (p 0.05) andA-Cdifferent letters indicate significant difference withthe SHS temperatures (p 0.05).Figure 4.11Effect superheated steam heat treatment on the138DPPH activity in reconstituted omega-3&6 plusmilk powder. Where, a–c different letters indicatesignificant difference with the SHS time (p 0.05)and A-C different letters indicate significantdifference with the SHS temperatures (p 0.05).Figure 4.12Principal Component analysis (PCA) biplot of SHS144reconstituted omega-3&6 plus milk powder volatilecompounds measured using SMPE–GCMS analysis.F1 and F2 are the first and second principalcomponentsFigure 4.13Principal Component analysis (PCA) biplot of SHSreconstituted omega-3&6 plus milk powder volatilecompounds measured using SMPE–GCMS analysis.F2 and F3 are the second and third principalcomponentsxxix144

Figure 5.1Changes in the lightness (L*) of raw milk during154sterilization by superheated steam heat treatment atdifferent temperature and holding time. Where, a–cdifferent letters indicate significant difference withthe SHS time (p 0.05) and A-C different lettersindicate significant differencewith the SHStemperatures (p 0.05).Figure 5.2Changes in the redness (a*) of raw milk during154sterilization by superheated steam heat treatment atdifferent temperature and holding time. Where, a–cdifferent letters indicate significant difference withthe SHS time (p 0.05) and A-C different lettersindicate significant differencewith the SHStemperatures (p 0.05).Figure 5.3Changes in the yellowness (b*) of raw milk during155sterilization by superheated steam heat treatment atdifferent temperature and holding time. Where, a–cdifferent letters indicate significant difference withthe SHS time (p 0.05) andA-C different lettersindicate significant differencewith the SHStemperatures (p 0.05).Figure 5.4Changes in acid value of raw milk during processingby superheated steam heat treatment at differentxxx158

temperatures 130-150 C and holding time 30-60second. Where, a–c different letters indicatesignificant difference with the SHS time (p 0.05)and A-C different letters indicate significantdifference with the SHS temperatures (p 0.05).Figure 5.5Effect of superheated steam heat treatment on160changes in POV value of raw milk by differenttemperatures and holding timeFigure 5.6Effect of superheated steam heat treatment on161changes of TBARS value of raw milk by differenttemperatures and holding timeFigure 5.7Effect of superheated steam heat treatment on163changes of P-AnV of raw milk by differenttemperatures and holding time.Figure 5.8Changes in Totox value of raw milk heated bysuperheated seam at different temperature andholding time. Where,a–cdifferent letters indicatesignificant difference with the SHS time (p erence with the SHS temperatures (p 0.05).xxxi164

Figure 5.9Changes in DPPH Value of raw milk treated by172superheated steam treatmentFigure 5.10Principal component analysis (PCA) biplot of SHS179raw milk volatile compounds measured usingSMPE–GCMS analysis. F1 and F2 are the first andsecond principal componentsFigure 5.11Principal Component analysis (PCA) biplot of SHS179raw milk volatile compounds measured usingSMPE–GCMS analysis. F2 and F3 are the secondand third principal componentsFigure 6.1Response surfaces and contour plots of (A) PV199(me.peroxide/kg), (B) P-AV, (C), TBARS (μmol/g),(D) DPPH radical scavenging activity (%), and (E)(TBC) of raw milk as a function of SHS processtemperature and timeFigure 6.2Fitted-line plot indicating the closeness betweenpredicted values and experimental values for (A) PV(me.peroxide/kg), (B) P-AV, (C), TBARS (μmol/g),(D) DPPH radical scavenging activity (%), and (E)TBC (c.f.u. ml-1) of raw milk as a function of SHSprocessxxxii201

Figure 7.1Impact different heat treatment on colour changes of212raw milkFigure 7.2Changes in viscosity and density value of raw milk214heated by SHS, microwave and convention methodsFigure 7.3Changes in acid value of raw milk during heated by216different heat treatment methods.Figure 7.4Changes in peroxide value of raw milk heated by219different heat treatment methods.Figure 7.5Effect of heat treatment methods on changes in218TBARS value of raw milk.Figure 7.6Changes in P-Anicidine value of raw milk by221different heat treatment methods.Figure 7.7Changes in pH value of raw milk by different heat222treatment methods.Figure 7.8Changes in DPPH radical of raw milk by differentheat treatment methodsxxxiii223

Figure 7.9Changes of vitamin C (ascorbic acid), A (Retinol)228and E (α-tocopherol) of raw milk heated by differentheat treatment methodsFigure 7.10Principal Component analysis (PCA) biplot of raw233milk volatile compounds heated by differentmethods measured using SMPE–GCMS analysis. F1and F2 are the second and third principalcomponentsFigure 7.11Principal Component analysis (PCA) biplot of rawmilk volatile compounds heated by differentmethods measured using SMPE–GCMS analysis. F2and F3 are the second and third principalcomponentsxxxiv233

LIST OF SYMBOLS/ ABBREVIATIONSymblos/AbbreviationCaption%Percentage CCelsiusµgMicrogramAa*RednessADVAcid Degree ValueANOVAAnalysis Of VarianceAOACAssociation Of Official Analytical ChemistsBb*YellownessCCDCentral Composite DesignDOEDesign Of ty Acid Methyl EsterFOMPReconstituted fortified milk powdergGramGCGas ChromatographyGC-MSGas Chromatography–Mass SpectrometryHPLCHigh Performance Liquid ChromatographyIUInternational UnitKgKilogramKcal/molKilocalorie per moleL*LightnessmeqMilliequivalentxxxv

mgMilligramminMinutemLMillilitermg/Lper milligram leterMUFAMonounsaturated Fatty AcidnmNanometerp-AnVP-Anisidine ValuePCPrincipal ComponentPOVPeroxide ValuePUFAPolyunsaturated Fatty Acidppmparts-per-millionRMRaw MilkRSMResponse Surface MethodologyRWMPReconstituted Whole Milk PowderSSecondsSFASaturated Fatty AcidSHSSuperheated SteamSPSSStatistical Package For Social ScienceTBARSThiobarbituric Acid Reactive SubstancesTBCTotal Bacteria CountUKUnited KingdomUSUnited StateV.ARetinolV.CAscorbic AcidV.EΑ- Tocopherolxxxvi

KESAN PEMANASAN STIM PANAS LAMPAU KE ATAS PERUBAHANBERKAITAN LEMAK DALAM SUSU CAMPURAN DAN SUSU SEGARABSTRAKSusu serta produk tenusu memainkan peranan penting bagi keperluan nutrisimanusia, dan menjadi sumber nutrisi utama di kebanyakan negara. Lemak danprotein merupakan kandungan penting di dalam susu, dan ianya boleh dipengaruhioleh beberapa faktor seperti bahan makanan, usia lembu dan pemprosesan haba.Susu merupakan elemen penting yang digunakan dalam penyediaan pelbagai jenismakanan contohnya pastri, pai, coklat dan kek serta ia berupaya meningkatkan ciriciri makanan seperti tekstur, warna, dan rasa. Dalam kajian ini, mod stim panaslampau (SHS) telah digunakan untuk memanaskan tiga jenis susu lembu iaitu, susutepung campuran semula penuh (RWMP), susu tepung campuran semuladiperkuatkan omega 3 & 6 (FOMP), dan susu mentah, pada suhu dan tempoh ma

3.3.9.b Effect of superheated steam (time and temperature) on MUFA composition 84 3.3.9.c Effect of superheated steam (time and temperature) on PUFA composition 86 3.3.9.d Effect superheated steam heat treatment on formation Trans fatty acids in reconstituted whole milk powder. 88 3.3.10 Effect superheated steam temperature and time on