Study of the Effect of Process Parameters on the Yield of Fermentable Sugar from Tuber Peels Via Acid and Enzyme Hydrolysis

The aim of this work is to study the acid and enzymatic hydrolysis of water yam peels using HCl, H2S04 acids and cellulase enzyme. The cellulase was secreted from Aspergillus niger (A.niger). The proximate analysis of the substrate showed that water yam peel is a lignocellulosic biomass with a cellulose composition of 48%. The effect of the process parameters (time, temperature, acid concentration and pH) on the yield of glucose in acid and enzymatic hydrolysis of the water yam peel was respectively investigated. Maximum glucose yield of 44.5% was obtained after 3 days of enzymatic hydrolysis at 30°C and pH 5. The HCl acid hydrolysis showed a maximum glucose yield of 27.3% at 70°C, 5% HCl after 180 minutes. The glucose yield in H2S04 hydrolysis was relatively lower than that of the HCl with a maximum yield of 26.5% at 70°C, 5% H2SO4 after 180 minutes. In addition to, the functional groups present in the glucose synthesized from ground water yam peels and the standard glucose were evaluated using Fourier Transformed Infrared (FTIR) Spectroscopy. The FTIR results showed similarities in the functional groups present in both sugars. Yam peel can be used for the production of glucose and further fermentative process to produce ethanol.

Diversity of Water Yam (Dioscorea alata L.) Accessions from Côte d’Ivoire Based on SNP Markers and Agronomic Traits

Dioscorea alata (L.), also referred to as water, winged, or greater yam, is one of the most economically important staple food crops in tropical and subtropical areas. In Côte d’Ivoire, it represents, along with other yam species, the largest food crop and significantly contributes to food security. However, studies focusing on better understanding the structure and extent of genetic diversity among D. alata accessions, using molecular and phenotypic traits, are limited. This study was, therefore, conducted to assess the pattern of genetic variability in a set of 188 D. alata accessions from the National Agronomic Research Centre (CNRA) genebank using 11,722 SNP markers (generated by the Diversity Arrays Technology) and nine agronomic traits. Phylogenetic analyses using hierarchical clustering, admixture, kinship, and Discriminant analysis of principal component (DAPC) all assigned the accessions into four main clusters. Genetic diversity assessment using molecular-based SNP markers showed a high proportion of polymorphic SNPs (87.81%). The analysis of molecular variance (AMOVA) showed low molecular variability within genetic groups. In addition, the agronomic traits evaluated for two years in field conditions showed a high heritability and high variability among D. alata accessions. This study provides insights into the genetic diversity among accessions in the CNRA genebank and opens an avenue for sustainable resource management and the identification of promising parental clones for water yam breeding programs in Côte d’Ivoire.

Pengaruh faktor lingkungan terhadap pertumbuhan beberapa aksesi Dioscorea alata L terpilih koleksi kebun raya purwodadi

Uwi (Dioscorea alata L.) merupakan jenis tanaman umbi-umbian berpotensi nutrisi. Namun pemanfaatannya sebagai bahan pangan alternatif masih jarang, karena keterbatasan informasi potensi nutrisi dan sistem budidaya. Penelitian ini bertujuan untuk menentukan faktor-faktor lingkungan yang berpengaruh terhadap pertumbuhan uwi. Penelitian dilakukan di lahan percobaan di Kabupaten Pasuruan, pada tujuh aksesi yang dipilih berdasarkan hasil penelitian sebelumnya, yaitu aksesi nomor 28, 36, dan 86 (Pasuruan), 42 dan 43 (Nganjuk), 57 dan 66 (Malang). Parameter lingkungan yang diamati meliputi suhu udara, kelembaban udara, intensitas cahaya, pH tanah, kelembaban tanah, jumlah dan jenis gulma. Hasil pengamatan dianalisis secara deskriptif dan statistik dengan uji Biplot menggunakan software Past 3. Hasil penelitian menunjukkan bahwa intensitas cahaya dan jumlah jenis gulma merupakan faktor lingkungan yang paling berpengaruh pada pertumbuhan tanaman uwi. Terdapat tiga grup aksesi tanaman uwi berdasarkan perbedaan faktor lingkungan yang mempengaruhi pertumbuhannya. Aksesi 42, 43 dan 57 dipengaruhi oleh suhu dan kelembaban udara, aksesi 28, 36 dan 66 dipengaruhi oleh intensitas cahaya dan aksesi 86 dipengaruhi oleh pH tanah. Analisis deskriptif menunjukkan bahwa sebagian besar gulma yang tumbuh merupakan tanaman invasif yang mempengaruhi pertumbuhan tanaman komoditas. Aksesi nomor 42, 43 dan 57 direkomendasikan untuk dibudidayakan di lahan sub optimal dengan kondisi pH asam dan minim air.AbstractWater yam (Dioscorea alataL.) is one of the tubers potentially as nutrition source. However, its utilization as the source of food alternative is still rare causes by limited information about its nutritional content and cultivation. The research aimed to determine the environmental factors effects the growth of water yam. The study was conducted in the trial site at Pasuruan with seven selected accessions of water yam based on previous research i.e. accessions number 28, 36 and 86 (Pasuruan), 42 and 43 (Nganjuk), 57 and 66 (Malang). The observed environmental parameters were the number and type of weeds, temperature, humidity, light intensity, soil pH, and soil moisture. The observations were descriptive and statistically analyzed using Biplot test with Past 3 software. The results showed that the light intensity and the number of weed species are the environmental factors that have the most affected on the growth of water yam plants. Accessions 28, 36 and 66 are affected by light intensity, accession 86 is affected by soil pH, and accessions 42, 43 and 57 are affected by air temperature and humidity. Most of the weeds grown in the study area are invasive species, which affect the growth of cultivated crops, so weeding is needed. Accession number 42, 43 and 57 adaptively grow in sub-optimum land with acidic pH conditions and minimum water capacity.

Genome-Wide Association Studies for Sex Determination and Cross-Compatibility in Water Yam (Dioscorea alata L.)

Yam (Dioscorea spp.) species are predominantly dioecious, with male and female flowers borne on separate individuals. Cross-pollination is, therefore, essential for gene flow among and within yam species to achieve breeding objectives. Understanding genetic mechanisms underlying sex determination and cross-compatibility is crucial for planning a successful hybridization program. This study used the genome-wide association study (GWAS) approach for identifying genomic regions linked to sex and cross-compatibility in water yam (Dioscorea alata L.). We identified 54 markers linked to flower sex determination, among which 53 markers were on chromosome 6 and one on chromosome 11. Our result ascertained that D. alata is characterized by the male heterogametic sex determination system (XX/XY). The cross-compatibility indices, average crossability rate (ACR) and percentage high crossability (PHC), were controlled by loci on chromosomes 1, 6 and 17. Of the significant loci, SNPs located on chromosomes 1 and 17 were the most promising for ACR and PHC, respectively, and should be validated for use in D. alata hybridization activities to predict cross-compatibility success. A total of 61 putative gene/protein families with direct or indirect influence on plant reproduction were annotated in chromosomic regions controlling the target traits. This study provides valuable insights into the genetic control of D. alata sexual reproduction. It opens an avenue for developing genomic tools for predicting hybridization success in water yam breeding programs.

Modeling of thin layer drying characteristics of blanch-assisted water yam (Dioscorea alata) slices

The thin layer drying characteristics of blanch-assisted water yam slices were investigated with respect to its un-blanched water yam slices in a convective hot air oven. The yam slices (diameter 4 cm; thickness 0.8 cm) were dried at temperatures 50, 60 and 70 °C, respectively with a constant air velocity of 0.13 m/s. The drying data obtained were fitted into six existing drying models: Page, Newton, Midilli, Henderson and Pabis, Logarithmic and Diffusion model. Non-linear regression analysis was used to determine the model parameters; the coefficient of determination (R2) and standard error of estimates (SEE) in order to determine the model best fit. The study showed that the drying process occurred in the falling rate drying period. The blanch-assisted slices had a faster drying rate than the un-blanched yam slices. Among the models, the diffusion model gave the overall best fit for the drying data obtained. The effective moisture diffusivity ranged from 3.18×10-8 to 4.47×10-8 m2/s for the blanch-assisted slices and from 4.73×10-8 to 7.33×10-8 m2/s for the un-blanched slices. The activation energies of the blanch-assisted and un-blanched yam slices were 15.5 kJ/mol and 20.1 kJ/mol, respectively. These processing conditions obtained for water yam flour would be suitable for its process design and control thereby enhancing its utilization and overall acceptability.

PHYSICOCHEMICAL PROPERTIES OF FLOUR AND STARCH OF PURPLE WATER YAM (Dioscorea alata) TUBER AND THE DIFFERENCE ON SENSORY ACCEPTANCE OF THE COOKIES PRODUCED

Purple water yam tubers (PWYTs) or Dioscorea alata are edible tubers containing bioactive compounds that are beneficial to human health. Its high carbohydrate content can be used to make flour or starch to increase its shelf life and food diversification. However, this food is unpopular among several communities in Indonesia, particularly for the juveniles due to limited processing knowledge. Therefore, this study aims to characterize the physicochemical properties of purple water yam flour (PWYTF) and starch (PWYTS) in order to assess consumers' acceptability toward gluten-free cookies. The PWYTF was prepared by drying peeled tubers, which was subsequently grounded. Meanwhile, the PWYTS was prepared by homogenizing the peeled tubers with water, the sediment from supernatant was dried. The chemical properties, such as moisture, ash, fiber, protein, and lipid, were determined using the Indonesian national standard procedures for flour. The physical properties, namely pH, bulk density (BD), water/oil absorption capacity (W/OAC), water/oil binding capacity (W/OBC), swelling power (SP) and solubility (Sol) were evaluated. The PWYTF and the PWYTS were used to make gluten-free cookies, with their physical properties and consumer's acceptability evaluated using semi-trained panelists. Yields of both the PWYTF and the PWYTS were 36.10% and 26.63%, respectively. The chemical compositions of the PWYTF and the PWYTS were significantly different (p0.05) for carbohydrate (80.34 and 80.78 %), crude protein (0.78 and 0.81%), and crude fiber (2.0 and 1.9%) except for the ash content (2.6 and 0.5%), lipid (0.3 and 0.1%), and moisture (13.77 and 15.70%). Furthermore, their physical properties were also significantly different (p0.05) for pH (6.62 and 5.84), BD (0.46 and 0.68 g/mL), WAC (2.07 and 0.46 g/g), WBC (1.07 and 0.49 g/g), SP, and Sol except OAC (1.63 and 1.49 g/g) and OBC (0.63 and 0.49 g/g). The cookies made from the PWYTS were appreciated with the highest hardness and rated from panelists. Therefore, the PWYTS can be used in place of a commercial wheat flour to make cookies..

Optimum Process Parameters and Thermal Properties of Moisture Content Reduction in Water Yam Drying

The determination of optimum process parameters for moisture content reduction in water yam drying using a hot air dryer was the aim of this work. Gravimetric method was used to determine the moisture content. Design of experiment was used with slice thickness, airspeed and temperature as the independent factors. Thermal properties such as effective moisture diffusivity and activation energy were determined. The result showed that slice thickness, airspeed and temperature have significant influence on the moisture content reduction. The effective moisture diffusivity ranged from 2.84 x 10-5 m2/s to 8.10 x 10-5 m2/s. The activation energy was 30.592kJ/mol. Minimum moisture content value of 11.98% was obtained at slice thickness of 2mm, airspeed of 2 m/s and temperature of 70oC. The quadratic model best described the drying process. The hot air dryer can conveniently be used for moisture content reduction in water yam slices which will increase its shelf life.