Investigating carotenoid loss after drying and storage of

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112 4. Ugandan field study Emenhiser et al. 1999). Similar levels of loss between sealed and non-sealed bags in this study can be explained by the high air permeability of LDPE. There were no differences in losses when the dried sweetpotato chips were stored in clear or opaque (black) bags (two-way ANOVA; p
113 4. Ugandan field study observed on Ejumula and Kakamega in various packaging types (Table 6). There was no correlation between dry matter and total carotenoid content in fresh sweet potatoes and losses in storage (p>0.05). Levels of loss after 4 months from chips of the six cultivars (70.4%) are consistent with levels of loss observed previously in various packaging after 4 months (68.2%). Considerable losses therefore occur in storage leading to a poor quality product. 4.3.5 Estimation of vitamin A activity in OFSP chips Vitamin A activities of various OFSP chips were estimated and summarised in Table 4- 9. Table 4-9: Estimation of vitamin A activity in flours made from OFSP cultivars after drying and storage for four months at room temperature (RE. kg -1 product on a fresh weight basis) Estimated vitamin A activity RE. kg Cultivar -1 product on a fresh weight basis* Freshly dried chips Stored chips (4 month) Ejumula 15,202 3,561 Kakamega 6,163 1,774 SPK004/1 5,413 1,777 SPK004/1/1 4,430 1,313 SPK004/6 10,235 2,942 SPK004/6/6 9,124 2,317 *1 RE=13 "g of all-trans-!-carotene (Haskell et al. 2004). All-trans-!-carotene content is estimated to 90% mean total carotenoids content (Rodriguez-Amaya and Kimura 2004; Bengsston et al. 2008; Bechoff et al. 2009a) . RE= Retinol Equivalents. Recommended daily requirements (RDA) of 2-6 year-olds is 400 RE (FAO/WHO 2002). Chips made from most of the cultivars had a high vitamin A activity after drying (>4,000 RE.kg -1 ) (FAO/WHO 2002) with an average of about 8,428 RE kg -1 (Haskell et al. 2004), but after four months of storage none of the chips (regardless of cultivar) had vitamin A activities greater than 4,000 RE.kg -1 ; the average was 2,281 RE kg -1 . In addition to the losses during drying and storage, it is speculated that further losses will occur during the preparation of OFSP flour into finished product (for example, atapa (traditional Ugandan porridge cassava/sweet potato), mandazi (traditional doughnut), or bread) would represent an estimated loss of a further 50% on a dry basis (Hagenimana et al. 1999; Kósambo 2004). Nonetheless, most of the cultivars immediately after drying
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Investigating carotenoid loss after
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DECLARATION I certify that this wor
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ACKNOWLEDGEMENTS I am deeply gratef
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CONTENTS CHAPTER 1.! LITERATURE REV
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4.3.2! Effect of trial and sweet po
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1.1 BACKGROUND 1.1.1 Introduction C
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3 1. Literature review It is estima
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5 1. Literature review food corresp
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- the leaves that make energy and s
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9 1. Literature review Uganda and M
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11 1. Literature review communicati
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13 1. Literature review soya grains
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15 1. Literature review Drying is a
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17 1. Literature review Modelling o
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19 1. Literature review Other types
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21 1. Literature review The perform
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23 1. Literature review degradation
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25 1. Literature review carotene an
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27 1. Literature review (Rees, NRI,
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29 1. Literature review red (>800 n
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31 1. Literature review Figure 1-17
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33 1. Literature review induced by
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35 1. Literature review Enzymatic c
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37 1. Literature review Volatile pr
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39 1. Literature review Carotenoid
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Table 1-5: Effect of type of proces
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Comparison of losses in drying proc
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45 1. Literature review observed we
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47 1. Literature review Different p
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Oxygen 49 1. Literature review Oxyg
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51 1. Literature review the storage
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2.2.2 Root samples 53 2. Assessment
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2.2.5 Water activity 55 2. Assessme
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57 2. Assessment of Methods below t
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59 2. Assessment of Methods !-carot
Page 71 and 72: 61 2. Assessment of Methods indicat
Page 73 and 74: 63 2. Assessment of Methods were we
Page 75 and 76: 65 2. Assessment of Methods Table 2
Page 77 and 78: 67 2. Assessment of Methods Intra-l
Page 79 and 80: 69 2. Assessment of Methods Signifi
Page 81 and 82: 71 2. Assessment of Methods Table 2
Page 83 and 84: Content (µg/g) Content (µg/g) Con
Page 85 and 86: 75 2. Assessment of Methods way-ANO
Page 87 and 88: 77 2. Assessment of Methods puree.
Page 89 and 90: Percentage loss "a" redness 45% 40%
Page 91 and 92: CHAPTER 3. 81 3. Preliminary study
Page 93 and 94: 83 3. Preliminary study Figure 3-1:
Page 95 and 96: 85 3. Preliminary study Air velocit
Page 97 and 98: 3.2.10 Statistical analyses 87 3. P
Page 99 and 100: 89 3. Preliminary study because it
Page 101 and 102: Sample area (cm2) 91 3. Preliminary
Page 103 and 104: Figure 3-9: UV-Visible spectrum of
Page 105 and 106: 95 3. Preliminary study Mulokozi an
Page 107 and 108: 97 3. Preliminary study One hundred
Page 109 and 110: 99 4. Ugandan field study respectiv
Page 111 and 112: Transmittance (%) 101 4. Ugandan fi
Page 113 and 114: 4.2.5 Total carotenoids extraction
Page 115 and 116: 105 4. Ugandan field study The dryi
Page 117 and 118: 107 4. Ugandan field study individu
Page 119 and 120: 109 4. Ugandan field study values a
Page 121: 111 4. Ugandan field study caroteno
Page 125 and 126: 115 4. Ugandan field study OFSP chi
Page 127 and 128: 117 5. Mozambican field study carot
Page 129 and 130: 119 5. Mozambican field study kg (p
Page 131 and 132: 121 5. Mozambican field study Table
Page 135 and 136: Tot. carotenoid content (!g/g) Tot.
Page 137 and 138: 127 5. Mozambican field study 5.3.6
Page 139 and 140: a b c c 129 5. Mozambican field stu
Page 141 and 142: 131 5. Mozambican field study Table
Page 143 and 144: 133 5. Mozambican field study #-car
Page 147 and 148: CHAPTER 6. 137 6. Effect of pre-tre
Page 149 and 150: 139 6. Effect of pre-treatment out
Page 151 and 152: 141 6. Effect of pre-treatment afte
Page 153 and 154: 143 6. Effect of pre-treatment leve
Page 155 and 156: 145 6. Effect of pre-treatment Citr
Page 157 and 158: 147 6. Effect of pre-treatment trea
Page 159 and 160: 149 6. Effect of pre-treatment inte
Page 161 and 162: CHAPTER 7. 151 7. Involvement of en
Page 163 and 164: 7.2.2. pH measurement 153 7. Involv
Page 165 and 166: 155 7. Involvement of enzymes glyce
Page 167 and 168: 157 7. Involvement of enzymes Table
Page 169 and 170: 159 7. Involvement of enzymes carot
Page 171 and 172: 161 7. Involvement of enzymes carot
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163 7. Involvement of enzymes Perox
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CHAPTER 8. 165 8. Study under contr
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Kilner jar (with metal lever catch
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Figure 8-2: Storage system for wate
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8.2.4 Carotenoid analyses 171 8. St
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8.3 RESULTS & DISCUSSION 8.3.1 Samp
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175 8. Study under controlled condi
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k (day-1) k (day-1) 0.10 0.08 0.06
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CHAPTER 9. GENERAL DISCUSSION AND F
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197 9. Discussion carotene loss aft
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199 9. Discussion total carotenoids
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9.4.2 Varietal influence 201 9. Dis
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203 9. Discussion 2008). The side e
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205 9. Discussion Absence of cis-is
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207 9. Discussion (Chapter 7). Howe
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209 9. Discussion of these cultivar
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References 211 References Aguayo, V
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213 References Bechoff, A., Dhuique
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215 References Chen, H.E., Peng, H.
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DIAS (2006) Semi-Annual and Annual
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219 References Tropical Agriculture
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221 References has a positive effec
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223 References Kamiya N. and Nagamu
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Lee, S.B. and Kim, K.J. (1995) Effe
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227 References Mills, R.C. and Hart
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Nestel, P., Bouis, H.E., Meenakshi,
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231 References Preston, C.M. and Ba
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Simon, P.W. (1997) Plant pigments f
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235 References Tran, T.H., Nguyen,
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237 References Walter, W.M., Purcel
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! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! A
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Arrhenius model: = ∞ − Ea RT ek
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242 Appendix 1 B/Calculation of Arr
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Temperature is integrated for each
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2) Integration of temperature in Ug
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Appendix 2b: Dryers cost in Lualua,
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250 Appendix 2 Technical informatio
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252 Appendix 2 Technical informatio
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Open air flat and sloped dryers 254
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Appendix 3: Total carotenoids metho
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4. Partition - Pour 40 ml of Petrol
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Publications: Publications, award a
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