Vacuum drying as a natural preservation method of post-harvest lemon might accelerate drying duration and produce the high-quality of dried lemon slices

Abstract

Lemon (Citrus limon B.) is one of the local fruits abundant in Indonesia. The dried lemon fruit was required for storage, extended shelf-life, minimizing decay, and simple distribution. This research applied vacuum drying to lemon slice dehydration in order to achieve quick times and preserve product quality. Vacuum drying with combinations of temperature (40, 50, 60 ^oC) and vacuum pressure (-38 and -69 cmHg) was applied to drying lemon slices until the final moisture content (9-11% w.b) was reached. The color, hardness value, and vitamin C content were analyzed on dried lemon slices. As a result, 60 °C with -38 cmHg indicates the fastest time to achieve a dry lemon slice and the highest hardness value. The 40 °C with -69 cmHg indicated the best vitamin C content of 76.40 (mg/100 g dw) and color value of L* (64.35 ± 0.57), H (77.0 ± 0.78), a*(6.43 ± 0.55), b*(27.92 ± 1.87), and c* (28.65 ± 1.91). The higher vacuum pressure accelerated the drying time and preserved the quality of the dried lemon slice. The higher temperatures led to the quality deterioration though also accelerate drying time. Experiment with more enhanced vacuum pressure and decreased temperature on lemon drying was required.

Keywords:
vacuum drying; lemon fruit; temperature; pressure; vitamin C