3.6 Impact of high CO2 on sugar accumulation and
weight loss reduction
The marked accumulation of major soluble sugars in
CO2-treated fruit suggests that is has better osmotic
adjustment. This has a significant influence on weight loss reduction in
fruit. Detailed data relating to weight loss are presented in Figure 6.
During LT storage, average weight loss throughout the early stage of
storage at 0 ºC was significantly lower in CO2-treated
strawberries in comparison to fruit stored in air. After 7 days of
storage at 0 ºC, the percent of weight loss was also more accentuated in
fruit stored in air than in the fruit pre-treated with
CO2 for 2 days. In this case, a reduction in weight loss
of 47-50% was recorded due to high CO2 treatment.
Weight loss did not exceed 1% at any stage during LT storage (Figure
8). When fruit were transferred to 20 ºC for 1 day, significantly less
weight was lost in fruit previously stored at low temperature than those
directly kept at 20 ºC. However, weight loss was not significantly
different between fruit with or without CO2. When SL was
prolonged for two days, water loss was significantly higher in fruit
stored in air than in CO2-treated fruit. Average weight
loss in SL+LTA was 1.0%, compared to 0.8% in SL+LTC and 1.5% in fruit
stored directly at 20 ºC. CO2-treated strawberries
showed the lowest weight losses after 2 days at 20 ºC. Present results
show that pre-treatment with 17% CO2 for 2 days limited
water loss during SL.
We speculate that increased soluble carbohydrate concentration is
engendered by a lower consumption of hexoses. This may be due in part to
its low availability as present results evidenced that reduced sucrose
breakdown by FvSS1, FvVINV1 and FvVINV2 avoiding water loss.