Coconut water processing using ultrafiltration and pasteurization

Green coconut water is traditionally consumed fresh, directed from the fruit at production regions. In order to allow its consumption in other regions, its industrialization demands a conservation process able to maintain its physic-chemical and sensory characteristics. Pasteurization is the main technique used for beverage preservation and microbiological safety. On the other side, membrane technology has been studied for conservation of beverages, due to their low temperature process conditions. The objective of this study was to evaluate the ultrafiltration and pasteurization processes for conservation of coconut water regarding the fresh product characteristics. Fresh coconut water was acquired from the local market in Rio de Janeiro city, immediately after extraction and cold to 15C. Ultrafiltration was conducted in a plate and frame unit composed of 20 kDa membranes. Process was carried out at 5 bar and 15C. Permeate flux was measured along the process. Pasteurization was performed in a tubular pasteurizer at 96C for 20 s. Samples were collected for determination of physic-chemical parameters, microbiological quality and sensory acceptability. Average permeate flux in ultrafiltration was 13 L/hm. Both processes were effective for reducing enzyme activity although decreasing total phenolics and soluble solids. Acidity and pH of processed waters were similar to fresh one. Microbiological analyses have shown that both processes provided safe products. On the other side, there was a significant difference in the acceptability of ultrafiltered water in relation to the fresh one. The obtained results indicate that both processes may be adequate for processing coconut water, although they need to be optimized regarding their sensory characteristics.