Assessing butter-head lettuce shelf life potential through fluorosensing can help growers in cultivating high quality produce and best commercial channel practices

Butter-head lettuce has a limited shelf life. Even when carefully handled and properly cooled a rather high variability in quality retention during commercialization and shelf life was observed.? It was hypothesized that pre-harvest factors determining the shelf life potential can be determined using a fast non-destructive optical technique called fluorosensing. Plant material is excited by four different excitation wavelengths one by one. At the same time the fluorescence is captured at three different wavelengths resulting in twelve signals (4 excitations x 3 emissions). Then several fluorescence excitation ratios are calculated that can be linked to plant constituents. This technique was used to evaluate the shelf life potential of butter-head lettuce at harvest. Hereto freshly harvested lettuce heads of eight local growers were transported to the cooperative facilities and measured with the optical technique before starting a simulation of the commercialization chain and shelf life. The lettuce was first cooled down over night to 2?C and then stored at 8?C and 50-60% RH for up to 6 days. During the simulation the quality was assessed on 1, 2, 3 and 6 days after harvest. An overall visual quality score was given and the brown red discoloration of the cut stem surface was measured using a Minolta color meter.? A high variability between growers and within growers was observed. Chemometrics techniques were used to link the fluorosensing data to the days when lettuce heads reached critical quality limits assessed by visual scoring or red discoloration of the cut stem surface. The feasibility of determining shelf life potential right after harvest in this way was evaluated. This information can be used to guide growers in cultivating high quality produce as well as to decide how and in which commercial channels the lettuce is best marketed. Sources Assessing shelf life potential of butter-head lettuce at harvest using fluorosensingBert Verlinden1, Bert Jacobs1, Joris Van Lommel2, Isabel Vandevelde2, An Decombel3, Peter Bleyaert3, Wouter Saeys4, Bart Nicola?11 KU Leuven, BIOSYST-MeBioS, Flanders Centre of Postharvest Technology, W. de Croylaan 42, 3001 Heverlee, Belgium2 Duffelsesteenweg 101, 2860 Sint-Katelijne-Waver, Belgium3 Ieperseweg 87, 8800 Rumbeke-Beitem, Belgium4 Kasteelpark Arenberg 30 - bus 2456, 3001 Leuven, BelgiumVIII International Postharvest Symposium, Cartagena, Spain, June 2016 Picture Minolta color meter, by?Aquateknica