Consumer freshness perception of spinach samples exposed to different storage conditions

The purpose of the present study was to perform freshness evaluation of spinach using a scale that reflects consumer perception of spinach freshness. Five different storage conditions with different air exposure levels and storage temperatures (4 °C and 15 °C) were selected from the preliminary test. Focus group interviews (FGIs) were conducted to develop a freshness scale by investigating consumer concepts and descriptions of freshness. A total of 338 consumers in Korea (n = 149) and the US (n = 189) participated in the sensory evaluation of spinach using the freshness scale developed from the FGI. In addition, physical measurements of spinach (weight and color) were performed and the correlation between the physical and sensory test results was analyzed.The freshness scale was developed by locating five descriptive terms on a 15 point category scale based on the FGI result: “Fresh as just purchased”, “Relatively fresh”, “Neither fresh nor wilted”, “Relatively wilted”, and “Too wilted to use”. The US scale used the best semantic translations to reflect the same freshness perception: “Very fresh”, “Fresh”, “Somewhat fresh”, “Not fresh, but acceptable”, and “Unacceptable”. The consumer group in both countries significantly distinguished the five samples from different conditions (p < 0.05). However, Korean and the US consumers gave different ranges of scores. Weight loss increased as spinach samples were more exposed to air and the freshness score was negatively correlated to % weight loss (r = −0.97, −0.93, Korea and the US, respectively). Color measurement results were not consistent across different conditions in both countries. Therefore, % weight loss could be used as a physical measurement method appropriate for the evaluation of spinach freshness.

► Freshness of spinach was evaluated by consumers as well as by physical measurements.
► A small difference in freshness perception was observed between Korea and the US.
► The freshness score was negatively correlated with % weight loss.
► The % weight loss could be used as a predictor of spinach freshness.