Effect of grapefruit seed extract and antibrowning agents on the keeping quality of minimally processed vegetables

Peeled garlic, cut onion and soybean sprouts were treated by dipping them in solutions of grapefruit seed extract (GFSE) and antibrowning agents, and microbial quality and browning were monitored during subsequent 7 day storage. Treatment by 250 mg.L-1 GFSE solution inhibited significantly the growth of microorganism on peeled garlic and cut onion, but reduced microbial population only marginally on soybean sprouts which have heavy microbial loads. The effect of a 250 mg.L-1 GFSE solution was comparable to that of a 100 mg.L-1 chlorine solution in decreasing microbial load and growth on peeled garlic and cut onion. Treatment by GFSE solution induced acceleration of browning for some products such as cut onion and soybean sprouts, necessitating a combined use with browning inhibitors. For the cut onion and soybean sprouts, GFSE treatment combined with antibrowning agents of citric acid and ascorbic acid could help to keep microbial load and browning down.