Abstract SCHIRACK, ANDRIANA VAIS. The Effect of Microwave ...

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decanal, 2,4-decadienal). A five point standard curve was used, and for all compounds, the linear fit had an R 2 ≥ 92%. The results of quantification (Table 5) support the descriptive panel comments used to describe the off-flavor. The microwave-blanched peanuts were described as being more burnt/ashy, which could be due to an increase in guaiacol, and more stale/floral, which could be due to the increase in phenylacetaldehyde. The samples were not differentiated in levels of acetophenone or nonanal. Although large FD differences were seen between the samples for toluene, quantification results did not support these differences, but the AEDA differences may have been complicated due to coelution with the solvent peak during GC/O. Threshold determination In order to clarify quantification results, threshold analyses were conducted to gauge human perception of these compounds. Detection threshold values for the quantified compounds which were not available in the literature were determined experimentally using the ASTM ascending forced choice method of limits procedure (Table 5). Because peanuts are composed of approximately 50% fat (Hoffpauir 1953), both the water and oil thresholds were evaluated. Based on these threshold values, guaiacol, phenylacetaldehyde, 2,6-dimethylpyrazine, and 2,3-diethyl-5- methylpyrazine had the most impact on the flavor of these samples. Phenylacetaldehyde, 2,6-dimethylpyrazine, and 2,3-diethyl-5-methylpyrazine concentrations in both control and off-flavored samples were above the threshold values. Not only were guaiacol concentrations in the off-flavored peanuts double 160
that of the control, but only in the off-flavored peanuts did the concentrations exceed the compound’s threshold in oil. Toluene, acetophenone, nonanal, decanal, and (E,E)-2,4-decadienal values were below the threshold values, either in the oil matrix or in both matrices. After threshold testing, the odor activity value (OAV) of each compound in different matrices was determined in the control and microwave-blanched peanuts (Table 5). The OAV is the ratio of the compound concentration in a food to its sensory threshold. The OAV can further identify those compounds having the most flavor impact (Guth and Grosch 1994). In Emmentaler cheese, a high fat food, the oil threshold value was chosen to calculate OAV for evaluation of key compounds because the lipid phase predominated in the samples (Preininger and Grosch 1994). Similarly in this study, the OAVs in oil were compared due to the high lipid content of peanuts. Phenylacetaldehyde, 2,6-dimethylpyrazine, 2,3-diethyl-5-methylpyrazine, and guaiacol had the highest OAV in oil of the compounds quantified. The OAV values of phenylacetaldehyde, 2,6-dimethylpyrazine, and guaiacol were the highest in the off-flavored samples and were also approximately twice their OAV values in the control, which further supported the role of these compounds in the flavor profile of microwave-blanched peanuts. Phenylacetaldehyde has been previously found in peanuts (Mason and others, 1967), in lavender honey (Bouseta and others 1996), and in other foods such as chocolate (Schieberle and Pfnuer 1999). Phenylacetaldehyde has also been linked to off-flavors, such as aroma deterioration in beer (Soares da Costa and others 2004) and rosy off-flavor in Cheddar cheese (Carunchia Whetstine and others 161
Page 1 and 2:
Abstract SCHIRACK, ANDRIANA VAIS. T
Page 3 and 4:
THE EFFEGT OF MICROWAVE BLANCHING O
Page 5 and 6:
BIOGRAPHY Andriana Schirack is orig
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TABLE OF CONTENTS v Page List of Ta
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Materials and Methods..............
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Table 3 High Impact Aroma-Active Co
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CHAPTER 1: INTRODUCTION 1
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The processing parameters used duri
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educed from 35-40% moisture to 8-10
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REFERENCES Adelsberg GD, Sanders TH
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Interdependency and underlying dime
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Composition of Peanuts The structur
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and Burma. The peanut prices in the
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(w.b.) within 3 days, large quality
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cdry = Specific heat of dry seeds (
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there is no direct correlation publ
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Peanuts are commonly stored in flat
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lanching has been imitated using a
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(1999), no detrimental effects of b
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when the air is distributed from ab
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y-product (Giese, 1992). Drying is
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the material to absorb electromagne
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ε' = Relative real permittivity (d
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oils, both ε' and ε" are low and
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1969). The flavor characteristics o
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et al., 1980). Likewise, sugars pre
Page 53 and 54:
n-methylpyrrole. Walradt et al. (19
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fact, Ory et al. (1992) suggested t
Page 57 and 58:
Flavor Research in Other Nuts Sever
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changed with time of roasting and i
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polyunsaturated acids that have a c
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hexanal are intensified to the high
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The results of temperature stress i
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Brown et al. (1977) found that the
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exhibited the fruity fermented off-
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(Pawliszyn, 2000). Also, the elevat
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compounds eluting from microwave-he
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Table 1: Peanut Volatile Analysis b
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the identification of volatile comp
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the detector. The compounds can the
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GC-O Applications High vacuum disti
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each half was allocated into one of
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Woody/Hulls/Skins Cardboard Table 2
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Givaudan-Roure developed Quantitati
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during high temperature microwave b
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OVM Organic volatiles meter Pa Pasc
Page 93 and 94:
References Abegaz EG, Kerr WL, Koeh
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odorants in high temperature cured
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17(4): 728-732. Mason ME, Waller GR
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partitioning constants and release
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Vercellotti JR, Crippen KL, Lovegre
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ABSTRACT Peanut blanching consists
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peanut moisture content from 5.5 to
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The computer monitored power output
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RESULTS AND DISCUSSION Energy Absor
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All treatments using the fan (F) ha
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Treatments 11NF, 8NF, and 5NF also
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lanchabilities as well as a longer
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microwave attain much higher temper
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REFERENCES ADELSBERG, G.D. and SAND
Page 121 and 122: TABLES AND FIGURES Table 1: Process
Page 123 and 124: Energy absorbed (kJ) 3000 2500 2000
Page 125 and 126: Temperature of peanuts (°C) 160 14
Page 127 and 128: Percent blanchability 100 90 80 70
Page 129 and 130: Maximum internal temperature (°C)
Page 131 and 132: ABSTRACT Microwave blanching of pea
Page 133 and 134: Several methods are used for blanch
Page 135 and 136: Peanuts MATERIALS AND METHODS Mediu
Page 137 and 138: Canada) on a laptop computer (Dell
Page 139 and 140: Sensory Analysis RESULTS AND DISCUS
Page 141 and 142: significantly lower final moisture
Page 143 and 144: ACKNOWLEDGMENTS Funded in part by t
Page 145 and 146: Foods and Beverages, Vol. 29, (G. C
Page 147 and 148: TABLE LEGENDS Table 1. Microwave ap
Page 149 and 150: TABLE 2. LEXICON OF PEANUT FLAVOR D
Page 151 and 152: Sweet Aromatic TABLE 4. CORRELATION
Page 153 and 154: CHAPTER 5: CHARACTERIZATION OF AROM
Page 155 and 156: Introduction The most common use of
Page 157 and 158: The objective of this study was to
Page 159 and 160: attributes which were different fro
Page 161 and 162: Volatile compounds from the solvent
Page 163 and 164: 0.25 μm df; J & W Scientific, Fols
Page 165 and 166: adjusted with the same concentratio
Page 167 and 168: characterized by the attributes of
Page 169 and 170: (E,E)-2,4-decadienal (fried/oxidize
Page 171: flavor dilution factors, nor did th
Page 175 and 176: e high enough for pyrazine formatio
Page 177 and 178: sensory panelists analyzing process
Page 179 and 180: References (ASTM) American Society
Page 181 and 182: Megahed MG. 2001. Microwave roastin
Page 183 and 184: Vercellotti JR, Mills OE, Bett KL,
Page 185 and 186: Table 2- Model system concentration
Page 187 and 188: 28 4-acetoxy-2,5-dimethyl- 3(2H)-fu
Page 189 and 190: Table 5 - Quantification, sensory o
Page 191 and 192: Conclusions This research investiga
Page 193 and 194: microwave technology may provide ma
Page 195 and 196: protect against colon, prostate, an
Page 197 and 198: APPENDICES 185
Page 199 and 200: SAFE (3 SAFE's can be done in 1 day
Page 201 and 202: 2. Turn off waterbath. 3. Turn off
Page 203 and 204: 5. Filter through a third sodium su
Page 205 and 206: contamination, and run a blank on t
Page 207 and 208: AC nutty/burnt 975 1.5 NB cabbage/g
Page 209 and 210: AC oxidized 1289 1.5 NB dusty/nutty
Page 211 and 212: NB brothy 1612 3.5 NB honey/hay 161
Page 213 and 214: Table 2: Aroma-Active Compounds in
Page 215 and 216: AC cedar 1081 3.0 AC burnt sugar/nu
Page 217 and 218: AC brothy 1350 2.0 NB garlic 1352 5
Page 219 and 220: NB fruity/floral 1670 3.0 NB rosy 1
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