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

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Microwave processing has been investigated as an alternative to traditional processing methods due to the speed of operation, energy savings, and efficient process control (Giese, 1992). Since heating takes place only in the food material and not in the surrounding medium, microwave processing can reduce energy costs. Shorter heating times also lead to greater nutrient retention, better quality characteristics such as texture and flavor, as well as increased production (Giese, 1992). The use of a continuous microwave system for blanching has been proposed as a means of reducing production time and energy costs during peanut processing. Previous studies at North Carolina State University have shown promise for the use of an industrial microwave system. Peanuts were effectively blanched by the microwave when the peanuts reached temperatures over 85 °C and final moisture contents of 6% or lower. In a study using a series of individual trays of peanuts passing through the microwave field, Rausch et al. (2005) examined the potential use of microwaves for peanut blanching. In the current study, refinement of the microwave applicator has allowed a solid bed of peanuts to be exposed to microwave energy in a continuous process, using a processing technique similar to that of Boldor et al. (2005). The best blanching efficiencies result from peanuts which are subjected to the highest temperatures during blanching and lose the most moisture. Moisture content affects blanchability as well as stability and flavor quality of peanuts (Adelsberg and Sanders, 1997; Katz, 2002). However, high temperature processing has been tied to the formation of off-flavors. For example, elevated temperatures are used during curing, in which the moisture content of the peanuts after digging is 4
educed from 35-40% moisture to 8-10% to prevent quality losses before further processing. It has been documented that curing peanuts at temperatures above 35 °C is related to the formation of anaerobic by-products which produce an off- flavor. Also, with increased curing temperatures above 35 °C, positive attributes such as roasted peanutty decrease while off-flavors such as fruity/fermented increase in intensity (Sanders et al., 1990). This decrease in positive flavor attribute intensity with increase in temperature has also been observed in dry-blanching (Sanders et al., 1999). Such changes in the quality and flavor of peanuts have been described previously using descriptive sensory analysis. Peanuts were first evaluated using a method called the Critical Laboratory Evaluation of Roasted Peanuts, or CLER (Holaday, 1971). Later, sensory lexicons for peanuts and peanut products were constructed by Oupadissakoon and Young (1984) and Syarief et al. (1985). A standardized lexicon was subsequently developed to address deficiencies in earlier models such as lack of differentiation of oxidized off-flavors and lack of sweet/caramel descriptors (Johnsen et al., 1988). The lexicon used in this research incorporates a ten point scale to rate intensity of flavor attributes using commercially available products as references (Sanders et al., 1989). Using descriptive sensory analysis, a processing-related off-flavor has been noted in peanuts undergoing high-temperature microwave blanching (Katz, 2002). The chemical cause of this off-flavor is not yet known. In other studies, specific volatile compounds identified by GC-mass spectrometry have been linked to sensory attributes in peanuts (Young and Hovis, 1990; Vercellotti et al., 1992). Instrumental 5
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
Page 7 and 8: TABLE OF CONTENTS v Page List of Ta
Page 9 and 10: Materials and Methods..............
Page 11 and 12: Table 3 High Impact Aroma-Active Co
Page 13 and 14: CHAPTER 1: INTRODUCTION 1
Page 15: The processing parameters used duri
Page 19 and 20: REFERENCES Adelsberg GD, Sanders TH
Page 21 and 22: Interdependency and underlying dime
Page 23 and 24: Composition of Peanuts The structur
Page 25 and 26: and Burma. The peanut prices in the
Page 27 and 28: (w.b.) within 3 days, large quality
Page 29 and 30: cdry = Specific heat of dry seeds (
Page 31 and 32: there is no direct correlation publ
Page 33 and 34: Peanuts are commonly stored in flat
Page 35 and 36: lanching has been imitated using a
Page 37 and 38: (1999), no detrimental effects of b
Page 39 and 40: when the air is distributed from ab
Page 41 and 42: y-product (Giese, 1992). Drying is
Page 43 and 44: the material to absorb electromagne
Page 45 and 46: ε' = Relative real permittivity (d
Page 47 and 48: oils, both ε' and ε" are low and
Page 49 and 50: 1969). The flavor characteristics o
Page 51 and 52: et al., 1980). Likewise, sugars pre
Page 53 and 54: n-methylpyrrole. Walradt et al. (19
Page 55 and 56: fact, Ory et al. (1992) suggested t
Page 57 and 58: Flavor Research in Other Nuts Sever
Page 59 and 60: changed with time of roasting and i
Page 61 and 62: polyunsaturated acids that have a c
Page 63 and 64: hexanal are intensified to the high
Page 65 and 66: The results of temperature stress i
Page 67 and 68:
Brown et al. (1977) found that the
Page 69 and 70:
exhibited the fruity fermented off-
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(Pawliszyn, 2000). Also, the elevat
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compounds eluting from microwave-he
Page 75 and 76:
Table 1: Peanut Volatile Analysis b
Page 77 and 78:
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
Page 85 and 86:
Woody/Hulls/Skins Cardboard Table 2
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Givaudan-Roure developed Quantitati
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during high temperature microwave b
Page 91 and 92:
OVM Organic volatiles meter Pa Pasc
Page 93 and 94:
References Abegaz EG, Kerr WL, Koeh
Page 95 and 96:
odorants in high temperature cured
Page 97 and 98:
17(4): 728-732. Mason ME, Waller GR
Page 99 and 100:
partitioning constants and release
Page 101 and 102:
Vercellotti JR, Crippen KL, Lovegre
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ABSTRACT Peanut blanching consists
Page 105 and 106:
peanut moisture content from 5.5 to
Page 107 and 108:
The computer monitored power output
Page 109 and 110:
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
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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
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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
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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 and 172:
flavor dilution factors, nor did th
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that of the control, but only in th
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e high enough for pyrazine formatio
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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,
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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
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microwave technology may provide ma
Page 195 and 196:
protect against colon, prostate, an
Page 197 and 198:
APPENDICES 185
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SAFE (3 SAFE's can be done in 1 day
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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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