Effect of Garlic Oil and Modified Atmosphere Packaging on the Quality of Chilled Shrimp

摘要

This research aimed to investigate the effect of essential oils extracted from garlic (Allium sativum L.) and modified atmospheric (MA) conditions on maintaining the quality of chilled Pacific white shrimps (Litopenaeus vannamei). Clean fresh shrimps (headless, shell-off and devein) were dipped into 15 mg/ml of garlic oil for 15 min. Approximately 100 g of shrimps with or without dipping into the garlic oil was placed on polyethylene terephthalate trays and packed under two MA conditions (modified atmosphere packaging 1: 40% CO_2 + 60% N_2 and modified atmosphere packaging 2: 60% CO_2 + 40% N_2) using nylon/PE pouches. The shrimps with or without dipping into the garlic oil packed under normal atmospheric condition using PE pouches were prepared as the control. The samples were then stored at 8℃ ± 2℃ for three weeks and taken every two times a week. Shrimp samples were subjected to physical, chemical and microbiological analysis as well as sensory evaluation. The results showed that either garlic oil or MA conditions had proven to help preserving the quality of chilled white shrimps because they slowed down both chemical degradation and microbial spoilage. The shrimps dipped in garlic oil and/or packed under MA conditions had lower pH, total volatile base nitrogen and trimethylamine values as well as total viable counts than the control sample. 60% CO_2 + 40% N_2 in combination of garlic oil helped prolonging the shelf life of the shrimps stored at 8℃±2℃ from 6 to 18 days. Thus, applying both garlic oil and low O_2 atmospheric conditions were more effective on maintaining shrimp quality than applying only garlic oil or MA conditions.