Experimental observations demonstrated that sweet potato cultivars with distinct flesh colors exhibited differential storability, though all varieties displayed progressively increasing decay rates during storage ( Figure 1A ; Table S1 ). After 60 days of storage, lines JK142 and JK328 showed minimal decay (≈0.4%) with no significant difference between them. Lines JK274, Xuzishu 8, Beijing 553, Jishu 25, and Yizi 138 exhibited decay rates of 2-4%—approximately 8 times higher than JK142/JK328, though this difference lacked statistical significance. In contrast, Xiguahong, Jishu 7, Hami, and Shangshu 19 displayed significantly higher decay rates (7-13%, p < 0.05), while lines JK7 and Yanshu 25 showed markedly elevated decay levels (17-22%, p < 0.01). Notably, line JK147 exhibited the highest decay rate (45.48%), measuring 113 times greater than those of JK142 and JK328. After 60 days of storage, Jishu 25 and Xuzishu 8 exhibited dry matter contents exceeding 32%, surpassing other cultivars. Line JK274 demonstrated intermediate dry matter levels (28–32%), while Jishu 7, JK142, Hami, JK328, JK7, Yanshu 25, Shangshu 19, Beijing 553, JK147, Xiguahong, and Yizi 138 all registered dry matter contents below 28% ( Figure 1B ; Table S1 ).

Experimental data demonstrated significant quality divergence among sweet potato cultivars with distinct flesh pigmentation during 60-day storage ( Figure 2 ; Table S2 ). Analysis of rotting rates revealed tiered deterioration patterns: JK142 and JK328 maintained optimal storability (0.4% rotting rate), JK274 and Xuzishu 8 showed moderate susceptibility (2-4%), Xiguahong exhibited higher degradation (7-13%), while JK7, Yanshu 25 (17-22%), and JK147 (45.48%) displayed severe physiological decline ( Figure 2A ). Dry matter content stratification occurred across three tiers: Jishu 25 and Xuzishu 8 (>32%) ranked highest, JK274 (28-32%) intermediate, and 11 remaining cultivars (<28%) lower ( Figure 2B ). Purple-fleshed varieties exhibited extreme anthocyanin variation (JK274:24.77 → Xuzishu 8:123.76 mg/100g), whereas yellow-fleshed cultivars showed progressive carotenoid accumulation (Jishu 25:9.58 → Xiguahong:37.42 mg/kg) ( Figures 2C, D ). Starch-type cultivars exhibited marked soluble sugar disparities (Hami 9.45% ↔ JK7 28.00%), with sucrose levels peaking in Shangshu 19 (25.53%) and starch content maximized in Jishu 7 (16.63%) ( Figure 2E ). All parameters displayed statistically significant cultivar-specific patterns (p<0.05), confirming flesh coloration as a critical determinant of postharvest performance.

Cluster analysis using squared Euclidean distance classified 14 sweet potato cultivars (lines) into three distinct groups based on standardized rotting rates and dry matter content ( Figure 3 ; Table S3 ). At a squared Euclidean distance threshold of 8, the cultivars segregated as follows: Group I comprised 11 materials (Jishu 7, Hami, JK7, Yanshu 25, Shangshu 19, JK142, JK328, JK274, Yizi 138, Xiguahong, Beijing 553) exhibiting moderate rotting rates and intermediate dry matter content (28-32%), collectively demonstrating enhanced storability, with the purple-fleshed line JK142 showing the highest storage resilience. Group II included two cultivars (Jishu 25, Xuzishu 8) characterized by elevated dry matter content (>32%) and moderate rotting rates (2-4%), representing intermediate storability, of which Jishu 25 displayed the maximal dry matter accumulation. Group III consisted solely of line JK147, registering the highest rotting rate (45.48%) combined with the lowest dry matter content (<26%), confirming its extreme susceptibility to postharvest deterioration.

The decay rate of sweet potato cultivar JK142 showed significant variations across different storage periods and concentrations of Chinese herbal treatments ( Figure 4 ; Table S4 ). At 15 days of storage, the 2% Artemisia argyi treatment exhibited markedly higher decay rates (8.89%) compared to the control group, representing the highest decay percentage among all treatments. By day 30, most treatments showed progressively increasing decay rates with varying escalation patterns, while the 2% Andrographis herba, 0.5% Perilla frutescens, 0.5% Artemisia argyi, 1% Prunella vulgaris, 0.5% Schizonepeta tenuifolia, and 2% Schizonepeta tenuifolia groups maintained stable decay rates. At the final observation (105 days), the lowest decay rates were recorded in both 0.5% and 2% Schizonepeta tenuifolia treatments, demonstrating the preservative efficacy of this herbal treatment for JK142 storage ( Figure 4A ).

After one month of storage, the sensory attributes of JK142 sweet potatoes showed gradual improvement with increasing concentrations of Andrographis herba and Prunella vulgaris. In contrast, treatments with Perilla frutescens and Schizonepeta tenuifolia initially reduced sensory quality before showing improvement at higher concentrations. Treatment with Artemisia argyi consistently decreased quality throughout the concentration range. After 105 days of storage, significant deterioration in overall sensory quality was observed, along with increased decay rates ( Figure 4B ). Regarding texture, hardness values of JK142 showed minimal variation under Andrographis herba, Perilla frutescens, Artemisia argyi, and Prunella vulgaris treatments, with no statistically significant differences. However, Schizonepeta tenuifolia-treated sweet potatoes maintained consistently higher hardness, peaking at 1% concentration ( Figure 4C ).

Initially, no significant differences were observed in weight loss rates across treatments. After 30 days of storage, however, 1% concentrations of Andrographis herba and Artemisia argyi significantly reduced weight loss in JK142 sweet potatoes. Throughout storage, 1% Artemisia argyi proved particularly effective at minimizing both water loss and nutrient depletion ( Figure 4D ). Dry matter content exhibited dynamic fluctuations during storage, generally declining over time. Notably, treatments with 0.5% Andrographis herba, 0.5% Artemisia argyi, 0.5% Prunella vulgaris, 2% Andrographis herba, 1% Prunella vulgaris, and 1% Perilla frutescens all effectively slowed dry matter loss ( Figure 4E ).

Compared to other herbal treatments, 1% Prunella vulgaris effectively reduced protein loss in sweet potato tubers during early storage. Protein content showed a general decline across all treatments over time, though 0.5% Andrographis herba maintained protein levels most effectively by day 105 ( Figure 4F ). Anthocyanin content under 0.5% Andrographis herba treatment was 1.4-fold higher than controls at day 15. By day 105, all treatments showed anthocyanin reduction, with 2% Artemisia argyi most effectively preserving anthocyanin content in JK142 ( Figure 4G ).

In our study, data processing and analysis were conducted using the Scientific Platform Serving for Statistics Professionals (SPSSPRO) to evaluate storage effectiveness rankings of sweet potatoes across different treatment groups. The results, presented in Table 1 , indicate the order of effectiveness from highest to lowest as follows: CK > 2% Andrographis herba > CK₁ > 1% Prunella vulgaris > 1% Andrographis herba > 1% Artemisia argyi > 2% Schizonepeta tenuifolia > 0.5% Andrographis herba > 2% Artemisia argyi > 0.5% Artemisia argyi > 0.5% Schizonepeta tenuifolia > 1% Perilla frutescens > 0.5% Perilla frutescens > 0.5% Prunella vulgaris > 2% Perilla frutescens > CK₂ > 1% Schizonepeta tenuifolia > 2% Prunella vulgaris.

As shown in Figure 5 , Jishu 25 potatoes showed no decay after 15 days when treated with: 1%Andrographis herba, 1% and 2% Perilla frutescens, 0.5% and 1% Artemisia argyi, 2% Prunella vulgaris, and 2% Schizonepeta tenuifolia ( Figure 5 ; Table S5 ). Throughout storage, decay rates remained low with 1% Andrographis herba, 0.5% Artemisia argyi, and 2% Schizonepeta tenuifolia treatments ( Figure 5A ). Sensory quality declined across all herbal treatments over time, with particularly severe deterioration in 0.5% Prunella vulgaris-treated potatoes during later stages ( Figure 5B ). Hardness initially increased then decreased with rising Andrographis herba and Perilla frutescens concentrations, while Artemisia argyi, Prunella vulgaris, and Schizonepeta tenuifolia treatments showed progressive softening. Notably, 1% Andrographis herba and 1% Perilla frutescens maintained consistently high hardness throughout storage ( Figure 5C ).

During early-to-mid storage, 1% Prunella vulgaris and 1% Schizonepeta tenuifolia treatments effectively reduced weight loss in Jishu 25. By day 105, 0.5% Prunella vulgaris best preserved moisture and nutrient content. Weight loss changes remained minimal with 1% Andrographis herba and 2% Artemisia argyi treatments throughout storage ( Figure 5D ). Schizonepeta tenuifolia at high concentrations maintained elevated dry matter content initially, while 0.5% Andrographis herba showed highest dry matter retention by day 105. Overall, 0.5% Andrographis herba, 1% Perilla frutescens, and 0.5% Schizonepeta tenuifolia all significantly preserved dry matter content during extended storage ( Figure 5E ).

Protein content declined across all Jishu 25 treatments except for 1-2% Perilla frutescens and 0.5% Artemisia argyi. Notably, 0.5% Perilla frutescens and 2% Prunella vulgaris treatments effectively mitigated protein loss during storage ( Figure 5F ). Carotenoid content was initially highest with 0.5% Artemisia argyi treatment. After 15 days, 1% Schizonepeta tenuifolia showed better performance. By day 105, carotenoid content increased significantly, with superior results from: 2% Andrographis herba, 2% Perilla frutescens, 2% Artemisia argyi, 0.5% Prunella vulgaris, and 1% Schizonepeta tenuifolia treatments ( Figure 5G ).

Subsequently, we processed and analyzed data using SPSSPRO to evaluate storage effectiveness rankings for sweet potatoes across different treatment groups. As shown in Table 2 , the treatments were ranked by effectiveness in descending order as follows: 0.5% Artemisia argyi > 2% Schizonepeta tenuifolia > 1% Andrographis herba > 0.5% Prunella vulgaris > 2% Andrographis herba > 2% Perilla frutescens > CK₁ > 2% Artemisia argyi > 2% Prunella vulgaris > CK > 1% Artemisia argyi > 0.5% Schizonepeta tenuifolia > 1% Perilla frutescens > 0.5% Perilla frutescens > CK₂ > 1% Schizonepeta tenuifolia > 1% Prunella vulgaris > 0.5% Andrographis herba.

Figure 6 demonstrates that the decay rate of sweet potato variety JK147 increases with extended storage duration ( Figure 6 ; Table S6 ). During mid-storage, 1-2% Perilla frutescens treatments effectively reduced decay incidence. Overall, 2% Artemisia argyi promoted decay, while 1% Andrographis herba and 0.5% concentrations of Artemisia argyi, Prunella vulgaris, and Schizonepeta tenuifolia better preserved freshness ( Figure 6A ). In late storage, sensory quality declined markedly - 2% Artemisia argyi-treated potatoes showed near-total decay. In contrast, JK147 treated with 0.5% Schizonepeta tenuifolia achieved the highest sensory scores, differing significantly from controls ( Figure 6B ).

Under Schizonepeta tenuifolia treatment, JK147 hardness gradually decreased, while 1% Andrographis herba and 1% Perilla frutescens treatments maintained consistently high hardness levels ( Figure 6C ). The 1% Prunella vulgaris treatment showed optimal performance during early and mid-storage of JK147, demonstrating the lowest weight loss rate. In late storage, low-concentration Artemisia argyi exhibited minimal weight loss variation with the lowest rate among all treatments ( Figure 6D ). Significant variations in dry matter content occurred across herbal treatments, with 2% Andrographis herba, 0.5% Prunella vulgaris, and 1% Schizonepeta tenuifolia most effectively preserving JK147 dry matter content ( Figure 6E ). Protein content declined variably with storage duration, though 2% Andrographis herba and 1% Prunella vulgaris treatments proved most effective at protein preservation and loss reduction ( Figure 6F ).

After 105 days of storage, treatments containing 1% Andrographis herba, 2% Perilla frutescens, 0.5% Artemisia argyi, 0.5% Prunella vulgaris, and 2% Schizonepeta tenuifolia showed the highest sucrose content ( Figure 6G ). During initial 15-day storage, 2% Andrographis herba and 2% Schizonepeta tenuifolia treatments yielded higher soluble sugar content than controls. By day 105, 1% Andrographis herba treatment maintained superior soluble sugar content compared to both water and untreated controls, demonstrating its effectiveness in reducing late-stage sugar loss ( Figure 6H ). Starch content analysis revealed that 1% Perilla frutescens showed initial superiority, while 0.5% Perilla frutescens performed better in later stages. Extended storage demonstrated that 0.5% Prunella vulgaris, 1% Schizonepeta tenuifolia, and 2% Andrographis herba treatments most effectively preserved JK147 starch content ( Figure 6I ).

In our study, data processing and analysis were performed using SPSSPRO to evaluate the storage effectiveness ranking of sweet potatoes across different treatment groups. As shown in Table 3 , the treatments are ranked by effectiveness in descending order as follows: 1% Prunella vulgaris > 1% Andrographis herba > CK₁ > 1% Perilla frutescens > 2% Andrographis herba > 2% Prunella vulgaris > 2% Perilla frutescens > 2% Schizonepeta tenuifolia > 0.5% Artemisia argyi > 0.5% Prunella vulgaris > CK > 0.5% Schizonepeta tenuifolia > CK₂ > 1% Schizonepeta tenuifolia > 0.5% Andrographis herba > 0.5% Perilla frutescens > 1% Artemisia argyi > 2% Artemisia argyi.

This study utilized five proprietary sweet potato cultivars from our laboratory collection: Jikezi 18 (JK274), Jikezi 19 (JK142), Jikeshu 20 (JK7), Jikeshu 21 (JK147), and Jikezi 22 (JK328). The experimental materials also included nine commercially grown varieties representative of eastern Hebei’s sweet potato production: Yanshu 25, Jishu 25, Jishu 7, Xuzishu 8, Shangshu 19, Beijing 553, Yizi 138, Hami, and Xiguahong.

The experiment employed three biological replicates per cultivar, each containing approximately 100 sweet potatoes. Tubers were packed in 40 cm × 70 cm polypropylene woven bags and stored for 60 days under controlled conditions. Post-storage evaluations included quantification of decay rate and dry matter content for each cultivar/line (Wang XJ., 2016; Wang ZY., 2016). Cluster analysis was performed to classify the 14 cultivars/lines based on their storage tolerance characteristics. Additionally, Pearson correlation analysis between decay rate and dry matter content provided preliminary insights into storage quality parameters.

The experimental design evaluated five traditional Chinese medicinal herb extracts at three concentrations (0.5%, 1%, and 2%), with CK serving as the blank control and CK1 as the aqueous control. A chemical control (CK2) using 500 mg/kg carbendazim was included. Treatment solutions were prepared by soaking herbs/chemicals in water for 2 hours, followed by tuber immersion for 30 minutes and subsequent air-drying. Each treatment group comprised 90 sweet potato tubers for primary evaluation, supplemented with 15 additional tubers for specific storage tolerance assessments. The experiment employed a triplicate design. Storage conditions maintained 12 ± 5°C and 70 ± 10% relative humidity for 105 days. Pre-storage measurements included tuber hardness (Wang ZY., 2016). Periodic evaluations at 0, 15, 30, and 105 days assessed decay rate, weight loss percentage, and sensory characteristics (Wang XJ., 2016). Anthocyanin and protein content were quantified at 15 and 105 days (Wang, 2012; Xiao, 2019), while dry matter content was determined at 0, 15, and 105 days.

The study utilized Jishu 25, a widely cultivated light yellow-fleshed sweet potato variety from eastern Hebei Province, selected for its moderate storage tolerance. Carotenoid content was quantified at three storage intervals (0, 15, and 105 days), while all other experimental procedures adhered to the methodology outlined in Section 4.4.

We selected JK147, a distinctive white-fleshed sweet potato line developed in our laboratory, characterized by low storage tolerance, for this investigation. Sucrose, soluble sugar, and starch contents were analyzed at three storage intervals (0, 15, and 105 days), while all other experimental protocols followed the methodology detailed in Section 4.4.