2018 ASHS Annual Conference

East Coast broccoli production decreases the time between harvest and purchase for East coast consumers. The objective of this experiment was to monitor the effect of storage temperature and time on broccoli grown on the East coast. A randomized complete block design was conducted using two broccoli varieties (Emerald Crown and Diplomat) obtained from a local grower. At harvest, broccoli was sorted into containers to establish four replications each of two storage conditions: 0°C (iced at harvest) and 5°C (cooled in storage). Broccoli heads of each variety were sampled weekly for seven weeks during postharvest storage, including the day of harvest. Florets were freeze-dried, ground, and analyzed for 13 glucosinolates, which included glucoprogoitrin (detrimental to health), glucoerucin, glucoraphanin and glucoiberin (anti-carcinogenic properties), and total glucosinolate content. A complete volatile profile was analyzed using the fresh frozen tissue. Volatiles reported are dimethylsulfide as an indicator of off-flavor volatiles, and 2-ethyl-furan, benzeneacetaldehyde, and 2-pentyl-furan as indicators of desirable flavor volatiles. Data were analyzed using mixed model analysis of variance (Glimmix procedure, SAS Institute, Cary, NC). Glucoprogoitrin was essentially undetectable in Diplomat broccoli and was greater in Emerald Crown broccoli stored at 0°C (P<0.05). Glucoiberin, glucoerucin, and glucoraphanin were found in significantly greater quantities in both cultivars stored at 0°C (P<0.05) compared to storage at 5°C. Glucoiberin was 59% greater in Emerald Crown than Diplomat broccoli (P<0.0001). Overall, broccoli stored at 0°C had greater total glucosinolate content (P=0.0001). Dimethylsulfide was greater in Diplomat broccoli (P=0.0007), broccoli stored at 5°C (P<0.0001), and at 42 days postharvest (P<0.0001). 2-ethyl-furan and 2-pentyl-furan were both greater in broccoli stored at 0°C (P<0.01) and at the day of harvest compared to all other days (P<0.0001). However, Emerald crown had greater concentrations of 2-ethyl-furan (P=0.0003), while Diplomat had greater concentrations of 2-pentyl-furan (P=0.0006). Benzeneacetaldehyde was greater in broccoli stored at 0°C for both varieties (P=0.012). Neither storage temperature nor time greatly affected nutritionally harmful glucosinolates. However, both cultivars of broccoli stored at 0°C had a higher concentration of anti-carcinogenic glucosinolates. As time and temperature increased, undesirable flavor volatiles increased and desirable volatiles decreased. This study indicates that storing broccoli at 0°C for no longer than 21 days is optimum to maintain the quality of desirable volatiles and anti-carcinogenic glucosinolates. Future experiments are needed to evaluate a broader range of postharvest temperatures for impact on these and other quality parameters.