Physicochemical characteristics of fiber rich flour from solid waste of purple sweet potato starch processing

Sweet potato starch processing produces liquid waste and solid waste. Solid waste from sweet potato starch processing contains a high concentration of fiber so that it can be used for making fiber flour, which can be used as material for food fiber fortification in foodstuffs. This study aims to evaluate the characteristics of fiber flour derived from the solid waste of purple-fleshed sweet potato (PFSP) starch processing. Starch processing is carried out using 3 different types of extracting ingredients, namely distilled water, 2000 ppm sodium metabisulfite solution, and 2000 ppm citric acid solution. The results showed that the yield of fiber flour produced was 4.07-5.11%. The resulting fiber flour has soluble and insoluble fiber content between 1.20-1.63 and 13.53-21.91% respectively. The results of this study indicate that fiber-rich flour from the solid residue of PFSP starch processing can be used as a fiber fortification agent in special food products for people with obesity.

Synthesis of Isomaltooligosaccharides (IMOs) from Sweet Potato Starch by Simultaneous Saccharification and Transglycosylation Using Saccharomyces cerevisiae Var. diastaticus BE 134 to Improve Purity of IMOs

This study developed a simple two-step procedure to produce isomaltooligosaccharides (IMOs) from low-cost sweet potato starch (SPS). Effect of various reaction parameters on the steps of the synthesis process of IMOs was systematically investigated. The results show that Spezyme Xtra enzyme was the most suitable for the liquefaction step. The oligosaccharide components’ contents, including G1–G10 and G2–G6, reached 73.95 ± 0.02% and 49.24 ± 3.19%, respectively, after liquefaction. The simultaneous saccharification and transglycosylation (SST) reaction of SPS followed the liquefaction after the α-amylase activity was deactivated. This reaction was simultaneously treated by β-amylase, pullulanase, and α-transglucosidase. The effect of various reaction parameters, consisting of solution pH, reaction temperature, enzyme dosage, and reaction time, on the SST reaction to synthesize IMOs from SPS was fully studied. The results showed that the highest concentration of IMOs (IG234) reached 68.85 ± 1.82 g/L at the optimal condition. The purification of pristine IMO was performed by adding Saccharomyces cerevisiae var. diastaticus BE 134 yeast cells at the final step of the procedure. In particular, the SST reaction for the synthesis of IMOs from SPS shortened SST reaction time by three times compared with other three-step synthesis procedures of IMOs. These findings show that the SPS-derived IMOs can be applied as a novel and inexpensive prebiotic healthcare product for human gastrointestinal health, dieters, and diabetics.

Engineering Properties of Sweet Potato Starch for Industrial Applications by Biotechnological Techniques including Genome Editing

Sweet potato (Ipomoea batatas) is one of the largest food crops in the world. Due to its abundance of starch, sweet potato is a valuable ingredient in food derivatives, dietary supplements, and industrial raw materials. In addition, due to its ability to adapt to a wide range of harsh climate and soil conditions, sweet potato is a crop that copes well with the environmental stresses caused by climate change. However, due to the complexity of the sweet potato genome and the long breeding cycle, our ability to modify sweet potato starch is limited. In this review, we cover the recent development in sweet potato breeding, understanding of starch properties, and the progress in sweet potato genomics. We describe the applicational values of sweet potato starch in food, industrial products, and biofuel, in addition to the effects of starch properties in different industrial applications. We also explore the possibility of manipulating starch properties through biotechnological means, such as the CRISPR/Cas-based genome editing. The ability to target the genome with precision provides new opportunities for reducing breeding time, increasing yield, and optimizing the starch properties of sweet potatoes.

Proximate Composition, Mineral and Sensory Properties of Orange-Flesh Sweet Potato Starch, Soybean and Groundnut Flour Complementary Food

Aims: This study was aimed at formulating and evaluating the proximate, mineral and sensory properties of complementary food from blends of orange flesh sweet potato (Ipomea batata) starch, soybean (Glycine max) and groundnut (Arachis hypogea) flour. Methodology: Orange flesh sweet potato starch (OFSP), soybean flour (SB) and groundnut flour (GN) were blended in the ratio of (OFSP:SB:GN): 90:5:5, 85:10:5, 80:15:5, 75:20:5, 70:25:5, 65:30:5, 60:35:5, 55:40:5, 50:45:5 and designated as PSG1 – PSG9, while 100% OFSP served as control. Evaluations were carried out following standard analytical methods. Results: Moisture, fat, ash, crude fibre and carbohydrate contents varied significantly (P<0.05) from 7.53 – 10.74, 1.33 -17.22, 1.20 – 1.94, 4.34 – 19.58 and 53.10 – 70.53% respectively. Protein content (7.62 – 21.91%) of the blends will meet >75% of safe level of protein intake for infants and children. Energy ranged from 339.45 – 373.07 Kcal/100g and will meet >55% of energy requirement for infants at 6 months. Ca, Cu, Fe, Mg and Zn varied respectively, from 0.68 - 6.07, 0.28 - 0.62, 4.40 - 11.94, 1.87 - 2.04, and 1.26 – 2.10 mg/100g. PSG complementary food in comparison to the recommended intake of minerals was found to be excellent in Cu, adequate in Fe and Zn but low in Mg and inadequate in Ca. Degrees of likeness for the sensory attributes: aroma, appearance, colour, taste, texture and overall acceptability varied from 5.00 - 7.00, 3.80 - 7.56, 5.04 - 7.20, 3.84 - 7.33, 3.88 - 7.56 and 4.29 - 6.96 respectively. These degrees of likeness from 3.84 - 7.56 indicated dislike moderately to like moderately. PSG7and PSG8 had significantly (P<0.05) the highest degrees of likeness for all attributes except for texture in PSG7 with neither liked nor disliked. Conclusion: This work showed that enriching orange flesh sweet potato starch by substituting with soya bean and groundnut, increased nutritional composition of the complementary food and addition of soybean flour up to 35 and 40% was acceptable to the assessors. This implies that this complementary food can be recommended as diet for newly weaned and older children.