Post-harvest Processing

Cassava

            In the regional trial, Rajah 3 gave the highest cassava yield at 37 ton/ha. Lakan 1 ranks first having flour yield of 11.53 ton/ha. Rayong 5 got the highest 34.89% grates or flour recovery. Rajah 3 was constantly highest in WHC (1.485 g/g) and WAI (0.490 g/g). NSIC CV – 39 had the highest hydration capacity but did not garner the lowest LGC.

Sweetpotato

            Ten sweet potato varieties were selected from NSIC recommended varieties and from the local or indigenous ones. The eight recommended varieties used were: VSP – 5 and 6, PSB SP – 16,- 17, NSIC SP – 31, 32, 33, and UPL SP – 3. The two indigenous varieties included Kasapad and Minamon, both from Dulag, Leyte. After the 2016 RDE Review, four more varieties were included as suggested by the panel; one was the recommended PSB SP – 15, and three local ones; the Tinagintim and Wonder which were obtained from Baybay City, and Kadabao to be sourced from Sogod, Southern Leyte. These varieties are considered high yielding with storage root yields of 14 ton/ha and above, high dry matter content of 32% and above, and suitable for flour processing with their storage root flesh colors from light yellow to white. All the recommended varieties were harvested within the prescribed period of 120 days days or 4 months, but for the native ones it took up to 8 months, being late maturing.

            Physical and processing chacteristics of tubers. The results showed that the peeling/ cleaning rate has increased from 20.54% to 24.80%, or an increase of 4.26%. The local varieties together with the three recommended varieties have constantly higher dry powder recovery compared to the rest of the evaluated varieties. Kasapad has the highest recovery of 28.83% in the minimal peeling. NSIC SP – 33 VSP – 5, PSB SP – 15 and 16 are more promising compared to the native ones in terms of the flour yield per hectare basis.

Sieve analysis. Sieve analysis on the powder product of VSP – 6 obtained an average Fineness Modulus of 0.87 which is classified as “Very Fine”. Particle size dimension was calculated as 0.0075 in. moisture content of the powder product ranges from 8 – 10% dry basis. EMC under ambient condition in PE packed form is 10 – 12%.

Flour functional and physico-chemical properties.

pH. Flour pH indicates the age of maturity on flour. Sweet potato flours without peel tested had pH above the mature point of 5.43-5.86, therefore ensuring freshness. If pH decreases ferom its most mature point, it will remain acidic and could not be attributed to flour maturity.

Flour hydration capacities. The capability of the flour to hydrate was determined through water holding capacity (WHC). Generally, with or without the addition of peel, all sweet potato flour remains unchanged.

Free radical scavenging activity. Antioxidant capacity of the flours were evaluated using this analysis. Sweet potato flours with peel have generally higher %DPPH inhibitions in which the highest inhibition was observed on VSP 5 flour with 88.20%