This study explored how enzyme type (cellulase and pectinase), concentration, and mixing ratio influence the functional compounds and antioxidant activities of purple sweet potato (Ipomoea batatas L.). The enzyme treatment significantly impacted all measured parameters. At a cellulase concentration of 30 units, the total anthocyanin content reached 399.4 mg/100g dry weight (DW), representing a 163% increase compared to the control (151.6 mg/100g DW). Total polyphenol (1,799.7 mg GAE/100g DW) and flavonoid (475.3 mg CE/100g DW) contents also peaked under these conditions, while higher enzyme concentrations or increased pectinase ratios reduced extraction efficiency. The highest ABTS radical scavenging activity was noted at 30 units of cellulase (954.0 mg TE/100g DW) and at 80 units in a combined treatment of cellulase (2) to pectinase (1) (927.2 mg TE/100g DW), suggesting that moderate enzyme synergy enhances antioxidant release. Conversely, DPPH activity decreased with higher enzyme concentrations, with all combined treatments yielding lower results than the control. Overall, the optimal condition for enhancing both functional compound extraction and antioxidant activity in purple sweet potato was identified as a single treatment with cellulase at 30 units.

This study developed a calibration model using near-infrared spectroscopy (NIR) for the rapid and non-destructive prediction of functional components—total polyphenols, total flavonoids, and antioxidant activities—in sweetpotato. Analysis of 473 sweetpotato genetic resources revealed significant variation and diversity in total polyphenols (4.67 to 2,419 mg/100g, CV 74.26%), total flavonoids (7.71 to 1,057.67 mg/100g, CV 122.88%), DPPH radical scavenging activity (7.83 to 532.56 mg/100g, CV 111%), and ABTS radical scavenging activity (11.84 to 615.87 mg/100g, CV 70.02%). The NIR spectra (400 to 2,500 nm), following pretreatment and modified partial least squares (MPLS) regression, were utilized to create the calibration model. Cross-validation indicated high predictive performance for total polyphenols (R2 cv 0.895), total flavonoids (0.940), DPPH (0.955), and ABTS (0.940). External validation yielded R2 ev values ranging from 0.623 to 0.726 and RPD values between 1.58 and 2.13, confirming the model's practical applicability for large-scale screening and classification. However, further enhancements are needed to improve the accuracy of quantitative analysis. Future studies should focus on refining the predictive model by incorporating samples from diverse genetic resources and cultivation environments. This research demonstrates that NIR spectroscopy can be effectively employed for the rapid, non-destructive evaluation of sweetpotato functional quality, facilitating the efficient selection of high-value cultivars.

This study optimized the extraction of β-carotene and antioxidant compounds from orange-fleshed sweet potato (Ipomoea batatas L.) using response surface methodology (RSM) with ethyl lactate as a green solvent. A central composite design (CCD) was utilized to evaluate how the solvent-to-sample ratio, temperature, and extraction time affected efficiency. The regression model was statistically significant (Adj. R2=0.67), revealing that the solvent-to-sample ratio was the most influential factor, while temperature and time had relatively minor effects. The optimal conditions identified were a ratio of 12 mL/g, a temperature of 35°C, and an extraction time of 30 minutes, which resulted in a yield of 27 mg/100g of β-carotene, along with high levels of polyphenols, flavonoids, and strong antioxidant activities as measured by DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline- 6-sulfonic acid)) assays. Validation experiments demonstrated a close alignment between predicted and experimental values, confirming the model's robustness. These findings indicate that ethyl lactate effectively extracts not only carotenoids but also a wide range of antioxidants, underscoring its potential as a sustainable solvent for developing functional food ingredients.

This study investigated the antioxidant characteristics of sweet potato according to different plant parts and drying methods. The sweet potato plant parts were divided into root tubers, stems, stalks, leaves, and tips, and the drying methods were freeze-drying and hot air drying. Total polyphenol and flavonoid contents and radical scavenging activity of the sweet potato plant parts were significantly different depending on the plant parts and drying methods. The total polyphenol content of freeze-dried sweet potato leaves and tips were 52.76 and 46.19 mg chlorogenic acid equivalents/g sample, and the total flavonoid contents were 222.47 and 214.12 mg quercetin equivalents/g sample, respectively, and decreased with hot air drying. DPPH radical scavenging activity was higher in freeze-drying than hot air drying and was significantly different depending on the plant parts. The ABTS radical scavenging activity of freeze-dried sweet potato leaves and tips were 43.48 and 44.68 mg Trolox equivalents/g sample, respectively, and decreased with hot air drying. Therefore, additional studies on the functionality of using by-products from sweet potato cultivation are needed.