Litchi is a special plant with a large area and yield in Luc Ngan district, the northern province of Bac Giang, Vietnam. However, litchi is easily damaged after harvest. Therefore, promoting the application of litchi preservation technology is always of interest.
To reduce losses in post-harvest preservation, improve production efficiency and increase incomes for people in the litchi growing region, the Institute of Chemistry under the Vietnam Academy of Science and Technology coordinated with Bac Giang provincial People’s Committee to conduct research on studying and applying technology to preserve and improve the quality of Luc Ngan litchi by Modified Atmosphere Packaging (MAP) presided over Dr. Pham Thi Thu Ha.
The research aims to develop a process for preserving litchi by MAP, to last up to the maximum time of four weeks for use, while preserving its quality and colour. It also study the method for litchi pretreatment and preservation by MAP, effect of post-preservation on quality and commercial value.
It has optimized technical parameters of MAP and conditions for litchi preservation, built a process and model for Luc Ngan litchi preservation by MAP with the scale of 5 tonnes.
Carried out from January 2015 to August 2016, the research investigated and evaluated the current state of litchi at present. MAP was created from thermoplastics such as polypropylen (PP) and polyetylen (LDPE). In the MAP manufacturing technology, these resins are used in primary plastics to ensure food hygiene and safety.
About the safety of the product, indicators of MAP have lower concentration than the level allowed by the Ministry of Natural Resources and Environment. It was licensed by the Department of Food Security and Safety.
The research studied several methods using MAP to preserve litchi and determined several conditions such as: the suitable ripeness of harvested litchi when preserving by MAP is from 80 to 85 days after fruiting; using hot water treatment at 47 0C for 7 minutes to reduced the rate of damage by pests; treating the litchi by Oxalic solution PH=3 for 6 minutes to maintain and stabilize colour; building a model of preserving 5-tonne litchi in 30 days with the damage rate of 9.83%. In addition, the research also completed the technical process of applying MAP to preserve litchi and nine scientific subjects.
With the obtained result, the research was highly appreciated by the VAST-level Appraisal Council. It received the excellent grade as its result has high practical application and can be multiplied.
Litchi preservation chest in the laboratory
Building the model of 5 tonne litchi preservation on June 21st and July 1st, 2016
Representatives from VAST inspected the litchi preservation model
Litchi preserved by MAP technology
Translated by Tuyet Nhung
Link to Vietnamese Version