Influence of maturity stage on nutritional quality and storage behavior of sweet potato roots

Abstract:

Maturity stage at harvest — the point at which the root is physically separated from the vine — determines both the nutritional value a consumer receives and the number of days that root can survive in storage. This research examined how four harvest dates (90, 110, 130, and 150 days after planting, DAP) influenced the nutritional composition and ambient storage behaviour of orange-fleshed sweet potato (cv. Bhu Sona) at Rajmata Vijayaraje Scindia Agricultural University, Gwalior, Madhya Pradesh, during 2021-22. Roots harvested at 130 DAP recorded the highest starch (22.4%), β-carotene (9.1 mg/100 g), and total sugar (6.8%) contents. Early harvest (90 DAP) yielded nutritionally inferior roots with thin, fragile skin prone to mechanical damage. Over-mature roots (150 DAP) showed declining β-carotene (8.4 mg/100 g) and increased fibre content (3.7 vs 2.8% at 130 DAP). In storage trials at ambient conditions (28±3 °C, 65% RH), roots from 130 DAP maintained marketable quality for 23 days — 8 days longer than 90 DAP roots and 4 days longer than 150 DAP roots. Weight loss and sprouting incidence were lowest in the 130 DAP harvest. These results identify 130 DAP as the optimal harvest window for Bhu Sona under Gwalior conditions, offering the best combination of nutritional quality and storage durability.