storage conditions, fatty acid, planting, and roasting affects of selected peanut varieties

142 Pages·2002·1.65 MB·English

by  George Baker

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FLAVOR FORMATION AND SENSORY PERCEPTION OF SELECTED PEANUT
GENOTYPES (ARACHIS HYPOGEA L.) AS AFFECTED BY STORAGE WATER
ACTIVITY, ROASTING, AND PLANTING DATE

By

GEORGE L. BAKER IV

A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA

2002
ACKNOWLEDGMENTS

I would like to thank all of my family, friends, and faculty at the University of
Florida for the care and guidance that they have given me through the past few years.
Thanks go to my committee members (Dr. Robert Bates, Dr. Daniel Gorbet, and Dr.
Steven Talcott) for their outstanding ideas, personal and financial cooperation, as well as
those who helped at the Marianna Research Station with the growing, grading and
shelling of the peanuts used in these studies. Many thanks go to John Cornell for the
suggestions, explanations, and analysis of statistical methods throughout my studies. My
appreciation goes to Timothy Sanders et al. and members of the North Carolina State
Food Science Department for roasting the peanuts discussed in the first chapter of this
dissertation. I would like to especially thank Dr. Sean F. O’Keefe and Dr. Charles A.
Sims, for their mentorship, financial assistance, and friendship. Last, but definitely not
least, I would like to thank my wonderful wife, Florian, for the love, patience, and
direction that only she could give.

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TABLE OF CONTENTS

Page
ACKNOWLEDGEMENTS…………………………...……………………….………….ii
LIST OF TABLES……………………………………………………………………..…vi
LIST OF FIGURES………..…………………………………………………………....viii
ABSTRACT……………………………………………………………………………...xi
CHAPTER

1 INTRODUCTION…….……..……..………………………………………………....1

2 REVIEW OF LITERATURE.………..……..……………………………………..….5

Overview…………………………………………………………………………...…5
History……………………………………………………………………………..…7
Peanut Growth……………………………………………………………….…….…7
Harvesting, Drying, and Storage………………………………………………..…….8
Nutrition…………………………..…………………………………………………..9
Peanut Storage, Stability, and Oxidation……….……...……..………..…………….11
Sensory……………………………………………….……………………..……….14
History and Uses……………………………………………….……………...14
Testing………………………………………………………………….……...15
Peanut Flavor………………………………………………………………….17
Planting Date and Peanut Maturity..…………………..……………………..……....18
Moisture…………………………………………………………..………………….20
Color Development………………………………………………………………......21
Applications………………………………………………………..……….....21
Theory………………………………………………………………………....22
Water Activity………………………………………………………..………………23
Formation of Peanut Flavor ……………………………………………….…....…...24
Peanut Roasting…………………………………………………………..…...24
Pyrazine Development……………………………………………………...…25
Solid Phase Microextraction (SPME)………………………………………………..29

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3 STORAGE WATER ACTIVITY EFFECTS, OXIDATION AND SENSORY
PROPERTIES OF HIGH-OLEIC PEANUTS…………………...……….…..33

Introduction…………………………………………………………………………..33
Materials and Methods…………………………………………………………….…34
Sample Preparation and Storage………………………………………………34
Lipid Extraction and Peroxide Value Determinations………………………...35
Sensory Analysis………………………………………………………..…….35
Statistics……………………………………………………………………….36
Moisture……………………………………………………………………….36
Sorption Isotherms……………………………………………………….……36
Results and Discussion………………………………………………………………36
Moisture……………………………………………………………………….36
Peroxide Values (PVs)………………………………………………………...37
Sensory Analysis………………………………………………………………37
Conclusions…………………………………………………………………….…….39

4 DETERMINATION OF PYRAZINES AND FLAVOR CHANGES IN
PEANUTS DURING ROASTING…………………………..………………………46

Introduction…………………………………………………………………………..46
Materials and Methods……………………………………………………………….48
Sample Preparation and Storage…………………………………………….…48
Peanut Roasting..………………………………………………………………49
Sensory Analysis..……………………………………………………………..49
Roast Color……………………………………………….……………………51
Moisture……………………………………………………………………….51
Solid Phase Microextraction (SPME)…………………………………………51
External Standard Preparation………………………………………….51
Sample Preparation……………………………………………………..54
Results and Discussion………………………………………………………………55
Conclusions…………………………………………………………….…………….63

5 FATTY ACID CONTENT, MOISTURE, AND SENSORY EVALUATION OF
STORED ROASTED PEANUT GENOTYPES FROM VARIOUS PLANTING
DATES…………………………….…………………………………………………93

Introduction…………………………………………………………………………..93
Materials and Methods………………………………………………………………95
Sample Preparation and Storage………………………………………………95
Sensory Analysis………………………………………...……………………96
Moisture.....……………………………………………………………..……..97
Roast Color...……………………………………………………………….....98
Fatty Acids…………………………………………………………………….98
Statistics……………………………………………………………………….99
Results and Discussion………………………………………………………………99
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Sensory Analysis………………………………………………………………99
Multiple Planting Date Genotypes (Main Effects)………………………….99
Single Planting Date Genotypes (Main Effects)………..………..……….101
Moisture………………………………………………………………………102
Fatty Acid Analysis…………………………………………………………..102
Conclusions………………………………………………………………………….104

SUMMARY AND CONCLUSIONS…..……………………………….……………116
APPENDIX
A TASTE PANEL SHEETS FOR CHAPTER 2………………..……..………….…118
B TASTE PANEL SHEETS FOR CHAPTER 3………..…………………………...121
C TASTE PANEL SHEETS FOR CHAPTER 4……..……………………………...122
REFERENCES…………………………………..……………………………….…….123
BIOGRAPHICAL SKETCH…………………………………………………………..130

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LIST OF TABLES

Table Page
2-1 Fat Comparison of Peanuts to Other Food Products………………………………....9
2-2 Vitamins and Minerals Present in Peanuts and Their Uses in the Body…………….10
2-3 Pyrazine Compounds Found in Peanuts…………………………………………….26
2-4 Odor Thresholds and Odor Descriptors of Selected Pyrazines (ppb) in Water……..26
3-1 Statistics for Sensory Parameters…………………………………………….……..45
3-2 Duncan’s Mean Separation for Sensory Ratings and Storage Water Activity……...45
3-3 Duncan’s Mean Separation for Sensory Ratings During Storage.………………….45
4-1 Balanced Incomplete Block Design for Panelist Presentation……………………...51
4-2 Selected Primary Pyrazine Concentration for Standard Curve…………………..…52

4-3 Linear Regression Equations and R2 values for External Pyrazine Standard………52
4-4 Main Effects of Roasting Treatments (Averaged Across All Genotypes) on
Sensory Attributes……………………………………………………………….…72

4-5 Effects of Roasting Time and Temperature on the Sensory Attributes of Peanut
Genotypes………………………………………………………..…………………..73

4-6 Effects of Roasting Time and Temperature for Pyrazines, L-value, and Moisture…74
4-7 Statistical Correlations Between Pyrazines, L-value, and Roasted Aroma for
Florunner……………………………………………………..………………….…87

4-8 Statistical Correlations Between Pyrazines, L-value, and Roasted Aroma for
Florida MDR 98……………………………………………………………………88

4-9 Statistical Correlations Between Pyrazines, L-value, and Roasted Aroma for
Georgia Greene……………………………………………………………...……..89
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4-10 Statistical Correlations Between Pyrazines, L-value, and Roasted Aroma
for SunOleic 97R…………………………………………………….……...…..90

4-11 Coded and Actual Prediction Equations for 2-Methylpyrazine, 2,5-
dimethylpyrazine, Total Pyrazines, L-value, Roasted Aroma and Roasted
Flavor for Florunner………………………..…………………………………….91

4-12 Coded and Actual Prediction Equations for 2-Methylpyrazine, 2,5-
dimethylpyrazine, Total Pyrazines, L-value, Roasted Aroma and Roasted
Flavor for Florida MDR 98...……………………..……………………………….91

4-13 Coded and Actual Prediction Equations for 2-Methylpyrazine, 2,5-
dimethylpyrazine, Total Pyrazines, L-value, Roasted Aroma and Roasted
Flavor for Georgia Greene…………………..………………………………….….92

4-14 Coded and Actual Prediction Equations for 2-Methylpyrazine, 2,5-
dimethylpyrazine, Total Pyrazines, L-value, Roasted Aroma and Roasted
Flavor for SunOleic 97R….………………..………………………………………92

5-1 Main Effects of Storage Time, Planting Date and Genotype on Sensory
Characteristics…………………………………………………………………….106

5-2 ANOVA Interactions for Multiple Planting Dates at Time 0..……….. ……...…..107
5-3 ANOVA Interactions for Multiple Planting Dates at 3 Months of Storage.………108
5-4 ANOVA Interactions for Multiple Planting Dates at 6 Months of Storage……….109
5-5 Main Effects of Storage Time and Variety on Sensory …………….. ……………110
5-6 ANOVA Interactions for Single Planting Date Genotypes..………………………111
5-7 Fatty Acid Percentage for Various Genotypes of Multiple Planting Dates ………112
5-8 Oleic/Linoleic Acid Ratio, Iodine Value, and Percent Saturation of Multiple
Planting Date Genotypes…………………………………………………………..113

5-9 Statistical Significance for Fatty Acids Related to Planting Date, Variety,
and Their Interaction……………………………………………………………..114

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LIST OF FIGURES

Figure Page
2-1 Summary of Autooxidation in Food Systems………………………………………13
2-2 Water Activity and Rate of Oxidation………………………………………………24
2-3 An Unsubstituted Pyrazine………………………………………………………….25
2-4 Maillard Reaction Pathway…………………………………………………………27
2-5 Proposed Alkylpyrazine Formation by Maillard Reactions………………………...28
2-6 SPME Extraction / Desorption Process…………………………………………….30
3-1 Moisture Changes During Storage at Various Water Activities……………………40
3-2 Peroxide Values During Storage at Various Water Activities……………………...40
3-3 Roast Peanutty Flavor During Storage at Various Water Activities……………….41
3-4 Crunchiness During Storage at Various Water Activities………………………….41
3-5 Cardboardy Flavor During Storage at Various Water Activities…………………..42
3-6 Painty Flavor During Storage at Various Water Activities………………………...42
3-7 Crunchiness and Moisture Content Correlation……………………………………43
3-8 Change in Moisture During Storage at Various Water Activities………………….43
3-9 Moisture Sorption Isotherms for High Oleic Peanuts……………………………....44
4-1 SPME Equilibrium……………………………………………………………….….54
4-2 Pyrazine Levels for Florunner at Various Roast Levels ……………………………65
4-3 Pyrazine Levels for Florida MDR 98 at Various Roast Levels ……...…………….66
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4-4 Pyrazine Levels for Georgia Greene at Various Roast Levels …………...………..67
4-5 Pyrazine Levels for SunOleic 97R at Various Roast Levels ……………...……….68
4-6 Total Pyrazines for Genotypes at Various Roast Levels …………………………..69
4-7 Hunter L-values for Genotypes at Various Roast Levels ………………………….70
4-8 Moisture Content for All Genotypes After Roasting ………………………………71
4-9 Least Square Means for Peanut Aroma…………………………………………….75
4-10 Least Square Means for Peanut Flavor...………………………………………...76
4-11 Least Square Means for Sweetness….……………………………………….….77
4-12 Least Square Means for Raw Flavor……………………………………………78
4-13 Least Square Means for Bitter Flavor…………………………………………..79
4-14 Least Square Means for Crunchiness…………………………………………...80
4-15 Linear Effects for Peanut Aroma Attribute When Roasted at 1500C…………..81
4-16 Linear Effects for Peanut Aroma Attribute When Roasted at 1750C…….…….81
4-17 Linear Effects for Peanut Flavor Attribute When Roasted at 1500C…….…….82
4-18 Linear Effects for Peanut Flavor Attribute When Roasted at 1750C…….…….82
4-19 Linear Effects for Sweetness Attribute When Roasted at 1500C………...…….83
4-20 Linear Effects for Sweetness Attribute When Roasted at 1750C………...…….83
4-21 Linear Effects for Raw Attribute When Roasted at 1500C………...……….….84
4-22 Linear Effects for Raw Attribute When Roasted at 1750C………...……….….84
4-23 Linear Effects for Bitter Attribute When Roasted at 1500C………...…..….…..85
4-24 Linear Effects for Bitter Attribute When Roasted at 1750C………...…..……...85
4-25 Linear Effects for Crunchiness Attribute When Roasted at 1500…...…..……..86
4-26 Linear Effects for Crunchiness Attribute When Roasted at 1750…...…..……..86
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5-1 Percent Oleic Acid for Peanut Genotypes Separated by Planting Date…………...114
5-2 Oleic/Linoleic Acid Ratio for Peanut Genotypes Separated by Planting Date……115

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