Postharvest of Peaches: Key to Quality

Peaches are exquisite and delicate fruits that require strict postharvest handling. From the tree to the consumer, every step is crucial to preserve their juicy texture, characteristic aroma, and food safety. Below, we review how to achieve this successfully.

Harvesting at the Ideal Time

To obtain a quality peach, the first step is harvesting it at its optimal ripeness. This is defined by:

• °Brix index ≥ 11
• Pulp pressure between 4 and 6 lb
• Background color turning creamy

Harvesting too early prevents aroma development, while doing it too late results in mealy pulp. Therefore, food technologists use refractometers and penetrometers directly in the field and organize harvesting shifts every 2 or 3 days to pick only “ready but firm” fruit.

Rapid Pre-cooling to Preserve Firmness

Peaches have a high respiration rate (20–30 mg CO₂/kg/h at 20 °C). A delay of more than 4 hours in cooling doubles the loss of firmness. To avoid this, the following is recommended:

• Hydrocooling or forced air cooling to 0–2 °C
• Storage with 90–95% relative humidity

This reduces enzymatic activity and ethylene production, the main cause of softening.

Delicate Sorting and Protective Packaging

Peach skin is very sensitive: damage occurs with just 2% deformation. Therefore, gentle transport systems are used, such as:

• Cup conveyors
• Slow-rotating brushes

Fruits with “pitting” or microcracks are discarded, and packaging is done in foam or molded pulp trays. For exports over 10 days, ethylene-absorbing sachets (potassium permanganate) are added.

Uninterrupted Cold Chain

During transport, maintaining a constant temperature between 0 and 1 °C is crucial. At –0.5 °C, chilling injury occurs, and above 5 °C, respiration triples. To prevent problems:

• Wireless data-loggers are used to detect deviations
• In case of thermal variation, modified atmosphere is applied (3% O₂ / 5% CO₂)

This system helps compensate for thermal stress and extends peach shelf life by 3 to 5 days.

Controlled Display at the Point of Sale

In stores, the fruit should remain no more than 48 hours at 18–20 °C. To maintain freshness, it is recommended:

• Fine misting to preserve humidity
• “Do not touch” signs to prevent damage
• Apply FIFO system and monitor °Brix daily

This way, consumers enjoy a peach with juicy texture, floral aroma, and guaranteed microbiological safety.