Aims: The objective of this study was to evaluate the effect of dilution ratio and pasteurization on physico-chemical parameters of Saba senegalensis pulp in the context of its recovery. Study Design: The experimental set-up was of a completely randomized design. Place and Duration of Study: This study was carried out in the Department of Food Science and Technology, at the Laboratory of Food Biochemistry and Tropical Product Technology (BATPTL) of Nangui Abrogoua University, Abidjan, Côte d'Ivoire, between June and August 2019. Methodology: The pulp collected from the fruit was diluted according to the following pulp/water ratio (RPW; v/v): 1:0.5; 1:1 and 1:1.5 and pasteurized at 75°C at different times (5 min, 10 min and 15 min). The pH, titratable acidity (TA), Total soluble solid (TSS), vitamin C, β-carotene and the colour were determined on the different samples. Results: The results obtained during this study showed that all the physico-chemical parameters evaluated, except pH, are affected during dilution while during pasteurization only vitamin C and β-carotene are affected. During the respective dilutions, 50%, 62% and 66% of the vitamin C concentration decreased as well as 53%, 74% and 76% of β-carotene. It also led to a decrease in total soluble solid (TSS) of 32%, 50% and 59%. Following the pasteurization of each diluted pulp12%, 45% and 50% on average of the vitamin C are lost at the respective pasteurization time  (5 min, 10 min and 15 min respectively). For β-carotene the content decreases (50%) within the first 5 minutes and remains constant during the last 10 minutes of pasteurization. Conclusion: During Saba senegalensis fruit processing into nectar, dilution and pasteurization factors must be considered in order to ensure the physico-chemical quality of the beverage. The physico-chemical characteristics were more affected during dilution than in pasteurization.

Aim: To prevent enzymatic browning during the freezing of yam slices of the Kponan variety (Dioscorea cayenensis-rotundata). Study Design: The experimental set-up was of a completely randomized design. Place and Duration of Study: Department of Food Science and Technology, Food Biochemistry and Tropical Products Technology Laboratory (BATPTL), University of Nangui Abrogoua, Abidjan, Côte d’Ivoire, between August and December 2018. Methodology: For this purpose, yam slices were either pretreated with a natural agent (lemon juice solution at different pH) or pretreated and blanched (85 °C for 2 min) and then packed in plastic bags and kept in the freezer at -18°C over a period of 4 weeks. Polyphenoloxidase and Peroxidase activities, Dry matter, rate of browning and sensory attributes of yam slices were determined. Results: The results showed a decrease in polyphenoloxidase and peroxidase activities regardless of the treatment. The largest decreases in activity were observed in yam slices that were both pretreated and blanched compared to the control (about 53.49% decrease in the specific activity of the PPOs and 51.46% of POD). The combination of pretreatment and blanching also resulted in lower dry matter yam slices compared to pretreated slices only. After 1 month of storage in the freezer, the lower rates of loss (browning) were recorded for the slices of yams that were both pretreated and blanched compared to the other methods which had very high losses. The pretreated and blanched slices had high dry matter content. The sensory profile of slices processed by the combined technique after one month of freezing had a good appreciation for all sensory characteristics of yam. Conclusion: In order to have a good product, the combined method is recommended for better freezer storage of yam slices.

All most of roots, tubers and seeds studied have been carried out under environmental control or glass. These methods had an advantage to minimize environmental effects on crop due to unequal distribution of the nutriment in the soil. This, have been often observed through the variability of size and form of the tubers harvested generally in farm condition. In order to evaluate the variations occurred on the nutritional (Ash, while protein and fat) and functional (clarity and swelling-solubility) values, yams cultivated in nursery gardener sachet have being compared to those of famer condition. This study has been conducted 2013-2014. Yam grown in nursery gardener sachet has the highest (p < 0.05) ash content (4.58 ± 2.18%) than this of field (1.53 ± 0.35%). Flour clarity is also affected by technical cultivation. This property is more improved by the cultivation in nursery gardener (p < 0.05). The cultivation in nursery gardener improved ash content and clarity of the suspension of yam flour.

Growing gradient into longitudinal axis of yam tuber was study through starch properties and nutritional composition of tuber parts (proximal, median and distal) during the tuberization. Two varieties of the complex D. cayenensis-rotundata (kangba and kponan) were used. Clarity, swelling and solubility, flow behavior and syneresis of starch and protein content, alcohol-soluble sugars of the flour were studies. The ash assessed by microanalysis. Starch clarity of tuber parts increased during the growth period. The proximal (56±2.06%) and median (54.5±1.09%) parts exhibited high clarity than the distal (48.2±2.56%) one. At earlier stage of tuberization, the viscosity ratio of tuber parts (var. Kponan) was weak. This indicates the possibility to use it as thickening agent in shearing sauce. Water loss decreased during the growth period for the three tuber parts. It was the same behavior for the swelling power. Concerning the nutritional composition of the flour, amount of protein did not influenced by the degree of tuber maturity. Alcohol-soluble sugars were higher at earlier stage of tuberization than at maturity of the tuber. Mineral content was appreciable at maturity than at beginning of the tuberization. The extent mineral according to their amount was: K, P, Mg and S. Starch properties such as clarity, syneresis and swelling were improved at maturity of the tuber. It was more for the proximal and median parts than the distal one. Yam tuber content a appreciable amount of protein and mineral at maturity.

Yam, like most roots and tubers, has a tissue variation that is responsible for the difference in cooking observed during culinary preparations. In order to understand the origin of this variation, this study was conducted through optical microscope and SEM observation of the beginning of tuberization. The local variety named Kponan of Dioscorea cayenensis-rotundata was used. The days after the beginning of the tuberization, the protrusion of the stem base intensified and gives rise to the tuber. The histological study of the onset of tuberization revealed once again the existence of a longitudinal growth gradient whose point of growth is the apex and the sense of maturity of the distal part at the proximal end. The cells birth at the apex and differ a little more towards the middle part of the tuber. The apex is the driving zone for the tuber's lengthwise growth. The cambial cells ensure this growth in length and thickness of the tuber. The tuber's growth activity decreases from the distal part to the proximal one. The distal part contains more vacuolated cells thus rich in water and less starch than the middle and proximal parts. The cell wall is thin and less lignified. The cambium generates cells at the lower end of the apex. These very vacuolated cells differentiate and will form the median and proximal parts of the tuber. The distal part will remain immature compared to the other two parts. This could explain the low dry matter and the origin of rejection or elimination of the distal part during culinary operations.