Sulfur dioxide preserves postharvest quality in table grapes

Energy metabolism plays a key role in fruit preservation

Table grapes are highly susceptible to softening, browning and decay after harvest, reducing their commercial value. A recent study investigated how sulfur dioxide (SO₂) preserves the quality of 'Munage' grapes, revealing that its benefits extend beyond disease control.

Researchers found that SO₂ fumigation maintained the visual quality of grapes during 60 days of storage at 0 °C, significantly reducing decay and delaying firmness loss. Treated fruit also better preserved soluble solids content and titratable acidity, two important quality parameters.

Mitochondrial protection maintains cellular energy

The study demonstrated that sulfur dioxide preserves cellular energy by enhancing the expression of genes involved in energy metabolism and increasing the activity of enzymes such as NAD kinase, ATPases and cytochrome c oxidase.

SO₂ treatment also promoted the accumulation of key intermediates of the tricarboxylic acid (TCA) cycle, including pyruvate, citrate, malate and succinate, helping maintain energy production during storage.

Electron microscopy analyses further showed that sulfur dioxide preserved mitochondrial membrane integrity and cristae structure while reducing oxidative damage and mitochondrial swelling, both closely associated with fruit senescence.

New insights into postharvest preservation

According to the authors, maintaining cellular energy metabolism is one of the main mechanisms behind the preservative effect of sulfur dioxide in table grapes. These findings provide new scientific evidence supporting its use to extend storage life, reduce postharvest losses and improve grape marketability.

Source

Zheng, Y., Zhang, Y., Xing, S., Wu, X., Zhang, G., Zhang, Z., & Wu, B. (2026). Sulfur dioxide delays quality deterioration by maintaining energy metabolism and mitochondrial structure in postharvest table grapes. Journal of the Science of Food and Agriculture. https://scijournals.onlinelibrary.wiley.com/doi/10.1002/jsfa.70861