Food Chemistry

3.8 Unsaponifiable Constituents 237 Monocyclic Carotenes γ-Carotene (ψ,β-carotene) (V) (3.123) β-Zeacarotene (Va) (3.124) Bicycl ...

238 3 Lipids This xanthophyll occurs in green leaves and in egg yolk. Keto Compounds Capsanthin (3, 3 ′-dihydroxy-β,κ-carotene-6 ...

3.8 Unsaponifiable Constituents 239 Violaxanthin is present in orange juice (cf. Ta- ble 3.57) and it also occurs in green leave ...

240 3 Lipids Bixin (XVIII) (3.138) Bixin is the main pigment of annato extract. Annato originates from the West Indies and the p ...

3.8 Unsaponifiable Constituents 241 bonds (Table 3.58). The fine structure of the spectrum is better distinguished in the case o ...

242 3 Lipids Table 3.59.Aroma compounds formed in oxidative degradation of carotenoids Precursora Aroma compound Odor threshold ...

3.8 Unsaponifiable Constituents 243 Fig. 3.48.Oxidative degradation of capsanthin dur- ing storage of paprika (according toPhili ...

244 3 Lipids (3.143) 3.8.4.5 UseofCarotenoidsinFoodProcessing Carotenoids are utilized as food pigments to color margarine, ice ...

3.9 References 245 by HPLC and thin layer chromatography. Thin layers made of MgO or ZnCO 3 are suit- able. These adsorbent laye ...

246 3 Lipids Foti, M., Piattelli, M., Baratta, M.T., Ruberto, G.: Flavonoids, coumarins, and cinnamic acids as antioxidants in a ...

3.9 References 247 Philip, T., Francis, F.J.: Oxidation of capsanthin. J. Food Sci. 36 , 96 (1971) Podlaha, O., Töregard, B., Pü ...

4 Carbohydrates......................................... 4.1 Foreword Carbohydrates are the most widely distributed and abundant ...

4.2 Monosaccharides 249 tetroses) and ketoses (starting from 2-pentuloses) undergo intramolecular cyclization with hemiac- etal ...

250 4 Carbohydrates Correspondingly,L-erythrose andL-threose are obtained fromL-glyceraldehyde: (4.5) The nitriles can also be d ...

4.2 Monosaccharides 251 Fig. 4.1.D-Aldoses inFischerprojection and D-arabino-2-hexulose. Such nomenclature makes it possible to ...

252 4 Carbohydrates (4.8) Fig. 4.2.D-Ketoses inFischerprojection (4.9) ...

4.2 Monosaccharides 253 The cis-arrangement of the two adjacent HO-groups in positions C-1 and C-2 ofα-D- glucopyranose, unlike ...

254 4 Carbohydrates The reaction rate for the conversion of the α-andβ-forms has a wide minimum in an aque- ous medium in a pH r ...

4.2 Monosaccharides 255 Table 4.5.Relative free enthalpies for hexopyranoses Hexopyranose Conformation G◦ (kJ/mole) α-D-Glucose ...

256 4 Carbohydrates tion a mixture exists of conformers similar in en- ergy (cf. Formula 4.18). (4.18) An anomeric effect prefer ...