Ce diaporama a bien été signalé.
Nous utilisons votre profil LinkedIn et vos données d’activité pour vous proposer des publicités personnalisées et pertinentes. Vous pouvez changer vos préférences de publicités à tout moment.

Farida Adam's results presentation

158 vues

Publié le

  • Soyez le premier à commenter

  • Soyez le premier à aimer ceci

Farida Adam's results presentation

  1. 1. Effect of Pod Storage and Farm Age on the Biochemical Composition, Fermentative Quality and Flavor Quality Characteristics of Fermented Cocoa Beans Presented by Farida Adam Supervisors: Prof. Emmanuel Ohene Afoakwa Prof. Agnes Budu
  2. 2. Introduction  Pod storage is a form of pre-conditioning that allows favourable conditions in the cocoa pod in order to begin the process of fermentation.  Studies have reported that pod storage positively affects chemical composition and aids in the development of the precursors (sugars and proteins) for the characteristic chocolate flavor  Pod storage increases pH and decreases non-volatile acids to levels where cocoa beans have a strong potential for developing higher flavours (Afoakwa et al., 2012 2
  3. 3. Main objective The main objective of this study is to investigate the effect of pod storage and farm age on the biochemical composition, fermentative quality and flavor quality characteristics of fermented cocoa beans in Ghana. Specifically: 1. To investigate changes in the chemical constituents, mineral composition, physical and physico-chemical composition of cocoa beans during fermentation from cocoa farms of different farm (tree) ages. 2. To investigate the effects of pod storage and age of farm (tree) on the biochemical composition (total sugars, reducing and non-reducing sugars, FFA) of fermented cocoa beans 3. To investigate the effects of pod storage and age of farm (tree) on the total polyphenol and anthocyanin content of fermented cocoa beans 4. To investigate the effects of pod storage and age of farm (tree) on the flavour quality characterictics of fermented cocoa beans using sensory and instrumental methods 5. To investigate the effects of age of farm (tree) and pod storage on the fermentative quality of cocoa beans from Ghana 3
  4. 4. Sample Preparation • Study sites : Asiakwa and Bosuso in the Eastern region of Ghana (4 Farmers’ farms) Harvesting (2400 pods) Pod breaking [1200 pods (aof x ft)] 1200 pods (aof x ps) Heap fermentation (0,3,6 days) Heap fermentation 6 days Pod storage (0,3,7,10 days) Pod breaking Sun drying on mats Storage (jute sacks) Lab analysis 4
  5. 5. Methods Laboratory analysis Chemical composition Proximate analysis (AOAC 2005 methods) Physico-chemical composition pH, Titratable acidity (AOAC 2005 methods) Biochemical composition Free fatty acids (AOAC, 2005) Sugars (Lane and Eynon described by James, 2005) Polyphenols and Anthocyanins Spectrophotometry Fermentative quality Cut test, colour, fermentative index Flavour analysis Descriptive sensory analysis with a trained panel 5
  6. 6. RESULTS 6
  7. 7. Objective 1 • To investigate changes in the chemical constituents, mineral composition and physico-chemical composition of cocoa beans during fermentation from cocoa farms of different farm (tree) ages • Methods – AOAC, 2005 7
  8. 8. Table 1: Effect of fermentation time on the proximate composition of cocoa beans from farms of different ages Age of Farm (years) Fermentation time (days) Moisture (%) Protein (%) Fat (%) Ash (%) Carbohydrate (%) 5 0 5.16 ± 0.03 17.35 ± 0.02 51.14 ± 1.19 5.07 ± 0.01 21.28 ± 0.16 3 5.29 ± 0.20 15.40 ± 0.01 48.68 ± 0.86 3.22 ± 0.02 27.41 ± 0.25 6 4.57 ± 0.12 15.17 ± 0.05 48.67 ± 0.89 2.57 ± 0.01 29.02 ± 0.19 15 0 4.62 ± 1.02 19.80 ± 0.10 50.89 ± 0.44 4.87 ± 0.03 19.82 ± 0.53 3 5.92 ± 0.07 19.63 ± 0.03 48.12 ± 1.13 3.49 ± 0.03 22.84± 1.05 6 6.65 ± 0.05 16.30 ± 0.02 48.45 ± 1.58 2.50 ± 0.01 26.10 ± 0.88 25 0 6.97 ± 1.63 17.88 ± 0.05 49.81 ± 1.11 4.58 ± 0.02 20.76 ± 0.16 3 4.99 ± 0.00 13.48 ± 0.02 49.64 ± 1.69 3.44 ± 0.02 28.45 ± 0.11 6 5.22 ± 0.17 13.83 ± 0.01 46.79 ± 0.46 2.22 ± 0.01 31.94 ± 0.09 31 0 5.37 ± 0.13 18.40 ± 0.02 49.68 ± 0.67 4.33 ± 0.05 22.22 ± 0.03 3 5.54 ± 0.05 18.15 ± 0.02 45.57 ± 0.76 3.83 ± 0.05 26.91 ± 0.51 6 6.77 ± 0.51 13.32 ± 0.02 46.49 ± 2.47 2.11 ± 0.01 31.31 ± 0.428
  9. 9. ANOVA summary table for chemical analysis Variables Moisture Protein Fat Ash Carbohydrate Age of Farm (AF) 0.50 3.46 3.14 5.47* 8.24* Fermentation Time (FT) 0.15 7.15* 9.65* 63.14 0.23 Interaction (AF x FT) 2.72 1247.05* 0.61 2.74* 3.12* 9 *Significant at P < 0.05
  10. 10. Table 2 Effect of fermentation time on the mineral composition of cocoa beans from farms of different ages Mineral content (mg/100g) ± Standard deviation Age of Farm (years) Fermentation time (days) K Mg Ca Cu Fe P 5 0 710.00 ± 2.00 1821.00 ± 1.00 13.80 ± 2.00 0.31 ± 0.20 1894.00 ± 3.00 548.00 ± 4.00 3 950.00 ± 1.00 2438.00 ± 1.00 34.10 ± 5.00 0.50 ± 0.10 1368.00 ± 2.00 499.00 ± 3.00 6 630.00 ± 1.00 1909.00 ± 2.00 50.00 ± 3.00 0.21 ± 0.11 1182.00 ± 2.00 422.00 ± 3.00 15 0 510.00 ± 5.00 2393.00 ± 3.00 37.00 ± 1.00 0.24 ± 0.14 1694.00 ± 2.00 411.00 ± 1.00 3 860.00 ± 3.00 2481.00 ± 1.00 16.00 ± 1.00 0.70 ± 0.10 1229.00 ± 1.00 333.00 ± 1.00 6 360.00 ± 2.00 4598.00 ± 2.00 54.00 ± 1.00 0.36 ± 0.20 1347.00 ± 1.00 384.00 ± 1.00 25 0 700.00 ± 2.00 2251.00 ± 1.00 27.00 ± 2.00 0.41 ± 0.11 797.00 ± 4.00 740.00 ± 0.00 3 910.00 ± 2.00 2602.00 ± 1.00 56.00 ± 1.00 0.52 ± 0.02 299.00 ± 5.00 704.00 ± 3.00 6 750.00 ± 2.00 2482.00 ± 1.00 75.70 ± 1.20 0.39 ± 0.03 508.00 ± 1.00 647.00 ± 3.00 31 0 620.00 ± 4.00 1273.00 ± 2.00 33.70 ± 2.50 0.49 ± 0.03 1550.00 ± 5.00 1532.00 ± 2.00 3 600.00 ± 5.00 938.00 ± 1.00 45.60 ± 2.00 0.10 ± 0.01 1316.00 ± 2.00 1799.00 ± 1.00 6 580.00 ± 5.00 3624.00 ± 1.00 82.50 ± 1.20 0.40 ± 0.01 915.00 ± 2.00 484.00 ± 1.0010
  11. 11. ANOVA summary table for mineral analysis Variables K Mg Ca Cu Fe P Age of Farm (AF) 2.87 1.28 2.71 0.28 24.52* 4.21 Fermentation Time (FT) 5.60* 2.46 10.96 0.40 12.44 1.34 Interaction (AF x FT) 1212.02* 291480.93* 30.24* 3.02* 2872.66* 217788.61* 11 *Significant at P < 0.05
  12. 12. Fig.1 The effect of farm age and fermentation time on the pH of cocoa beans (nibs) 5 5.5 6 6.5 5 15 25 31 pH Farm age (years) 0 days 3 days 6 days 12
  13. 13. Figure 2: The Effect of Farm age and Fermentation Time on Titratable Acidity of Cocoa Beans 0 0.002 0.004 0.006 0.008 0.01 0.012 0.014 0.016 0.018 0.02 5 15 25 31 Titratable acidity(g/100ml) Farm Age (years) 0 days 3 days 6 days 13
  14. 14. ANOVA summary table for pH and TTA Variables pH TTA Age of Farm (AF) 1.11 12.30* Fermentation Time (FT) 5.28* 6.68* Interaction (AF x FT) 638.63* 0.01* 14 *Significant at P < 0.05
  15. 15. Objective 2 • To investigate the effects of pod storage and age of farm (tree) on the biochemical composition (total sugars, reducing and non-reducing sugars, FFA) of fermented cocoa beans • Methods – Free fatty acids (AOAC, 2005) – Sugars (Lane and Eynon described by James(2005)) 15
  16. 16. Fig 3:The Effect of Farm age and Pod Storage on Free Fatty Acid Content of Cocoa Beans 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 0 3 7 10 FFA (%) Pod storage (days) 5 years 15 years 25 years 31 years Maximum limit (1.75%) 16
  17. 17. Fig 4:The Effect of Farm age and Pod Storage on Total Sugar Content of Cocoa Beans 0 10 20 30 40 50 60 70 0 3 7 10 total sugars (mg/g) pod storage (days) 5 years 15 years 25 years 31 years 17
  18. 18. Fig 5:The Effect of Farm age and Pod Storage on Reducing Sugar Content of Cocoa Beans 0 10 20 30 40 50 60 0 3 7 10 reducing sugars (mg/g) pod storage (days) 5 years 15 years 25 years 31 years 18
  19. 19. Fig 6:The Effect of Farm age and Pod Storage on Non-Reducing Sugar Content of Cocoa Beans 0 2 4 6 8 10 12 0 3 7 10 non-reducing sugars (mg/g) pod storage (days) 5 years 15 years 25 years 31 years 19
  20. 20. Objective 3 • To investigate the effects of pod storage and age of farm (tree) on the total polyphenol and anthocyanin content of fermented cocoa beans • Methods - Spectrophotometry 20
  21. 21. Fig 7:The Effect of Farm age and Pod Storage on Non-Reducing Sugar Content of Cocoa Beans 0 10 20 30 40 50 60 70 0 3 7 10 Anthocyanin content (mg/kg) Pod storage (days) 5 years 15 years 25 years 31 years 21
  22. 22. Fig 8:The Effect of Farm age and Pod Storage on Non-Reducing Sugar Content of Cocoa Beans 22 0 20 40 60 80 100 120 140 160 0 3 7 10 Total polyphenol content (mg/g) Pod storage (days) 5 years 15 years 25 years 31 years
  23. 23. Fig 9:The Effect of Farm age and Pod Storage on O-diphenol Content of Cocoa Beans 23 0 5 10 15 20 25 30 35 0 3 7 10 O-diphenols (mg/g) Pod storage (days) 5 years 15 years 25 years 31 years
  24. 24. Objective 4 • To investigate the effects of age of farm (tree) and pod storage on the fermentative quality of cocoa beans from Ghana • Methods – Cut test – Colour (Hunter Lab) – Fermentative index (Spectrophotometry) 24
  25. 25. Table 3 : Effect of pod storage on the cut test of cocoa beans from farms of different age Age of farm pod storage Deep purple (%) Pale purple (%) Brown (%) Slaty (%) Mouldy (%) 5 0 13 15 70 2 0 3 19 12 69 0 0 7 23 16 56 5 0 10 2 18 80 0 0 15 0 7 13 77 3 0 3 0 18 79 3 0 7 6 31 62 1 0 10 0 0 55 1 44 25 0 2 1 93 4 0 3 2 6 79 11 2 7 0 5 64 31 0 10 0 5 59 36 0 31 0 1 10 89 0 0 3 7 8 85 0 0 7 12 3 85 0 0 10 1 1 29 69 0 25
  26. 26. Fig 10:The Effect of Farm age and Pod Storage on the Colour of Cocoa Beans 24 28 32 0 3 7 10 L- value Pod storage (days) 5 years 15 years 25 years 31 years 26
  27. 27. Figure 11 : The Effect of Pod storage and Age of Farm on the Fermentative Index of Fermented Cocoa Beans. 0 0.5 1 1.5 2 2.5 3 3.5 4 0 3 7 10 FermentativeIndex Length of pod storage (days) 5 years 15 years 25 years 31 years Well fermented cocoa beans 27
  28. 28. Objective 5 • To investigate the effects of pod storage and age of farm (tree) on the flavour quality characterictics of fermented cocoa beans using descriptive sensory methods • Method – Trained sensory panel 28
  29. 29. Figure 12: Flavour profiling of Cocoa Liquor by trained sensory panel 29 0 2 4 6 8 10 colour intensity aroma intensity taste flavour intensity intensity of after taste 0 days 0 2 4 6 8 colour intensity aroma intensity taste flavour intensity intensity of after taste 7 days 5yrs 15yrs 25yrs 31yrs
  30. 30. Conclusions • Fat was the highest chemical constituent irrespective of farm age but the younger farms produced beans of better chemical constituents for chocolate quality as protein, ash and fat decreased with age. • Younger farms also produced beans with relatively lower pH values (more acidic) by the end of fermentation which are likely to have better flavour quality. • Irrespective of farm age, FFA levels remained acceptable for up to 10 days of pod storage however there were increases in total and reducing sugars after the 7th day of pod storage. Sugar content was influenced significantly by farm age. • The fermentative quality was acceptable as fermentative index values were above 1, good brown colour was retained and the highest proportions of brown beans were obtained after 10 days of pod storage irrespective of age. • Flavour intensity decreased in younger farms after 7 days with aroma and colour intensity decreasing for older farms 30
  31. 31. Recommendations • The influence of individual agronomic practices and farm age on cocoa bean quality should be investigated • Instrumental flavour analysis should be done to give more information on flavour quality 31
  32. 32. Acknowledgement • Supervisors (Prof Afoakwa and Prof. Budu) • Staff and students of the Nutrition and Food Science Dept (especially, Prof Saalia, Joyce, Nana Serwah Boateng and sensory panel) • Farmers (Wofa Adam, Wofa Sammy, Wofa Emma and Elder Richard) 32
  33. 33. Thank You 33

×