Exploring the impact of packaging on broccoli rabe florets

In a recent study that has relevance for organic farming, food processing and consumer health, researchers have explored how packaging and storage affect the nutritional and sensory qualities of organic broccoli rabe florets.

Broccoli rabe (Brassica rapa subsp. sylvestris) is a traditional leafy vegetable in Italy and beyond, valued for its pungent taste, resilience in organic farming, and richness in bioactive nutrients. With growing consumer demand for organic produce, minimally processed vegetables now represent a growing segment in retail markets. However, packaging and modified atmosphere storage can change internal gas balances, leading to nutrient loss or the build-up of unwanted volatiles.

Led by the National Research Council of Italy, the research revealed that minimally processed florets undergo profound metabolic and transcriptomic shifts during storage. In packaged samples, carbohydrate reserves were found to decline significantly, while stress-responsive amino acids and organic acids increased.

Notably, under low-oxygen conditions, florets redirect carbon into γ-aminobutyric acid (GABA) and lactic acid (LA) accumulation — compounds with known health relevance. By linking gene expression changes with metabolite profiles, the study mapped the molecular routes that drive these alterations, offering insights for both quality preservation and consumer health. The results have been published in Horticulture Research.

For their study, the researchers investigated two genotypes of organic broccoli rabe across two production years, comparing freshly harvested florets with those stored fresh or packaged for four days. They used untargeted nuclear magnetic resonance profiling and RNA-seq to unravel the metabolic and gene expression changes that occur in different storage conditions, focusing particularly on the pathways leading to GABA and LA accumulation.

The researchers quantified 25 water-soluble compounds, including amino acids, carbohydrates and organic acids, and performed principal component analysis to track differences among freshly harvested, stored fresh, and packaged florets.

Packaged samples showed the sharpest divergence, with carbohydrate levels dropping by more than 50%, while amino acids such as phenylalanine and valine rose by over 30%. Stress-related organic acids including succinic acid and α-ketoglutaric acid increased by more than 75%. Significantly, GABA levels surged to over 8 mg/g dry weight in packaged florets, compared with negligible amounts in freshly harvested samples. Lactic acid, absent in fresh tissues, also accumulated under packaging conditions, reflecting hypoxia-induced fermentation.

The team developed a detailed gene–metabolite map of 175 genes and 14 metabolites, providing a molecular blueprint of the stress-driven reprogramming. They concluded that low-oxygen packaging conditions trigger a carbohydrate sink into GABA and LA pathways, underscoring both nutritional opportunities and quality management challenges.

“Our findings highlight how a common post-harvest practice — packaging — fundamentally reshapes the metabolism of organic broccoli rabe,” said Donato Giannino, senior author of the study.

“The rise in GABA and lactic acid is a double-edged sword. On one hand, these compounds are associated with beneficial effects such as blood pressure regulation and gut health. On the other, the metabolic reprogramming reflects stress conditions that could shorten shelf life if unmanaged. Our gene–metabolite network provides a valuable resource for designing better storage solutions while safeguarding both nutritional and sensory quality.”

By clarifying how packaging conditions accelerate GABA and lactic acid accumulation, the research could help to guide improvements in modified atmosphere packaging to balance nutrient enhancement with freshness preservation. Producers may then use these insights to tailor packaging strategies that maintain flavour while boosting health-promoting compounds.

In the longer term, the research could inform breeding programs for stress-resilient varieties with naturally elevated levels of functional nutrients.

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