Science of Retaining Produce Freshness

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Fresh produce includes several fruits and vegetables that are delicious and rich in several essential nutrients. However, you may often find it challenging to maintain their freshness. Most food items tend to perish and deteriorate over time. Fortunately, there are several ways to identify whether the produce is fresh by examining its color, texture, and aroma.

You may have already seen store shelves where fruits and vegetables often remain crisp, flavourful, and nutritious. This is because retail businesses are often aware of advanced preservation techniques that they use to ensure an efficient food supply chain. Every individual or entity must ensure the freshness of food items to prevent nutrient loss and extend their shelf life. This also helps minimize food waste.

This guide explores the key factors affecting fresh produce quality and the most effective
methods to preserve its freshness.

Factors Leading to Loss of Freshness and Nutritional Value in Fresh Produce

Did you know that over 25% to 50% of fruits and vegetables are lost while being transported from farms to direct consumers? Most of these items are a part of fresh produce, which means all of them are susceptible to spoilage within a period. This involves getting exposed to biological, or chemical elements of nature.

As the produce spoils, its nutritional value can significantly decline. This results in a loss of vitamins, antioxidants, and minerals. The produce also deteriorates further when exposed to heat, humidity, or improper handling. This nutrient depletion reduces the health benefits of the food and affects its market value.

Now, let’s understand the relevant factors that contribute to freshness loss and nutrient loss in several food items or fresh produce:

Temperature Sensitivity

Fresh produce is highly sensitive to temperature fluctuations. A very high or low temperature can increase microbial growth in several food items, ultimately spoiling them and making them useless over time.

Incorrect storage temperatures can cause some fruits to decay within some time. The best examples here are bananas and avocados, which are among the most perishable fruits.

Optimal temperature management easily slows down metabolic reactions, which helps preserve the freshness of several fruits and vegetables.

Moisture Loss and Dehydration

Water content helps maintain the texture and appearance of fresh produce. Loss of moisture and dehydration can cause leafy greens, berries, and cucumbers to shrivel, soften, and wilt.

Ethylene Gas

Ethylene is a gaseous plant hormone that helps ripen fruits instantly, such as bananas, apples, and tomatoes.

An Overview of the Ethylene Control Process

Treatments that decrease the level of ethylene in fruits retard their ripening and preserve the nutrient value. Here’s a detailed look into the process:
  • Internal Ethylene Concentration: Reducing or controlling the internal ethylene concentration processes helps slow fruit ripening and extend its shelf life. This allows the fruit to stay fresh longer by minimizing exposure to ethylene and delaying the natural ripening process.
  • Oxygen Absorption: In this process, the oxygen level is decreased, which helps slow down metabolic activities in fresh produce and causes a delay in ripening. Lower oxygen levels always reduce the rate of respiration, which delays the ripening process and preserves the quality of the fruit.
  • COModulation: Increasing carbon dioxide levels helps maintain the freshness of unprocessed fruits and vegetables. Higher CO₂ levels also slow down the respiration rate and the entire ripening process of the fruit or vegetable.
  • Treatment with Chemicals: This is a complicated procedure that helps with ethylene synthesis, a chemical reaction that delays ripening. Auxins, cytokinins, and gibberellic acid have an opposite effect to that of Abscicic acid and Ethylene. These chemicals easily help regulate the ripening process to preserve the fruit’s freshness.
  • Ionising Radiation: Low doses of X-ray or gamma radiation also help slow down ripening without compromising the food quality. This treatment reduces ethylene production and delays the onset of over-ripening.
  • Regulating the Temperature: Keeping fruits and vegetables at low temperatures helps prevent premature ripening and spoilage, preserving the produce’s appearance and nutritional value.

Identification and Measurement of Fresh Produce

You must be able to identify and measure freshness loss in fresh produce immediately. This involves considering several aspects, with the most common ones discussed below:

Visual Indicators

Texture, smell, and taste are the three visual indicators that help you identify underlying issues in fresh produce. The following table gives you a detailed overview of these three indicators in understanding the quality of fresh produce.

Category

Indicators

Texture

Softness or mushiness

Smell

Sour or fermented odour

Taste

A bitter or off-flavour

Other Indicators

There are a few other indicators that can help analyse freshness in fresh produce:
  • Sensory Evaluation: Analysing appearance, firmness, aroma, and flavour to determine freshness and detect early signs of spoilage.
  • Gas Composition: Anyone can control ripening and prevent premature spoilage by monitoring oxygen and carbon dioxide levels in storage
  • Smart Packaging Sensors: Embedded sensors make it easier to detect temperature fluctuations, gas changes, and microbial activity.

Traditional vs. Industrial Methods for Fresh Produce Freshness Retention

You can easily refrain from the freshness of fresh products by leveraging both traditional and industrial methods. However, you must also know the differences between both methods to select the one that suits your requirements the best:

The following table draws a detailed comparison between traditional and modern methods of retaining freshness:

Category

Traditional Methods

Industrial Methods

Nutritional Value Point

Retains more vitamins and natural enzymes with minimal intervention.

May lead to loss of nutrients because of excessive preservative usage. However, a few modern techniques retain key vitamins and minerals.

Storage Conditions

Cool,      dry      storage      in well-ventilated areas

Refrigeration, food storage bags, controlled atmosphere storage

Preservation Approach

Natural intervention

Advanced preservation techniques

Shelf Life

Requires

immediat

e consumption

Extended through temperature control and gas regulation

Ethylene Control

Depends on natural separation of produce

Requires   CO₂    modulation,

ethylene inhibitors, and smart packaging

Moisture Retention

Natural    hydration

through leaves or

roots

Humidity control in cold storage and packaging

Microbial Prevention

Washing and sun-drying to reduce bacteria

Ionizing radiation, chemical treatments, and antimicrobial packaging

Usage

Common in households and small markets

Used in large-scale food industries and supply chains

Methods and Techniques to Retain Freshness in Fresh Produce

Industry professionals are researching and working hard to suggest methods and techniques that can retain freshness easily. These are:

Refrigeration and Cooling

  • Lowering the temperature slows down respiration rates, delaying ripening and
  • Reduces microbial growth by preserving food safety and
  • Different food products require specific temperatures. Leafy greens can be kept fresh at 0–2°C, while tropical fruits like bananas should be stored above 10°C.

Modified Atmosphere Packaging (MAP)

MAP changes the gas composition inside the packaging, which slows down spoilage. It includes:
  • Gas Regulation: Adjusting oxygen (O₂), carbon dioxide (CO₂), and nitrogen (N₂) levels helps delay ripening and inhibit microbial growth.
  • Fruit-Specific Packaging: Customised packaging is based on a fruit’s respiration rate to increase freshness. It will be easier to retain the freshness of fruits like strawberries with low O₂ and high CO₂ levels. Other fruits like apples require a balance of O₂ and CO₂. This can easily prevent overripening.

Moisture Control

Proper moisture regulation prevents dehydration and spoilage in fresh produce. Key methods include:

  • Humidity Control: The right humidity levels in storage always help reduce moisture loss. Most fruits and vegetables need a relative humidity of 90% to 95%.
  • Ethylene Gas Management: Ethylene accelerates the ripening and spoilage of food. CO₂ modulation, ethylene-absorbing packets, and ventilation are relevant techniques that help extend shelf life.

Freeze Shock and Freeze Burn in Fresh Produce

  • Freeze Shock: Sudden exposure to freezing temperatures can damage all the cells in fresh produce. This may deteriorate the texture of food items and also lead to loss of moisture content.
  • Freeze Burn: This is a condition that occurs when the fresh produce is exposed to extremely cold, dry conditions for extended periods. This results in extreme dehydration, discoloration, and loss of texture.

Best Practices for Consumers to Retain Freshness

You can easily retain the freshness of fruits and vegetables at home by leveraging relevant techniques. This involves following the steps below that help you extend the shelf life of food items and maintain their quality.

Proper Storage at Home

All fruits and vegetables have a shelf life that often varies depending on their texture or other factors. Make sure to store these fresh produce properly when keeping them in your kitchen. For instance, you must refrigerate leafy greens and berries to ensure longevity. Conversely, bananas and tomatoes must always be kept at room temperature.

First-In-First-Out (FIFO) Method

FIFO is a method that involves organizing and managing food items in a particular manner. This technique is based on the principle that whichever food item is stored first must be consumed first.

This means you must consume older produce before starting with the new ones. Organize your storage areas so that you can easily access and use all the older items. You must also frequently check for signs of spoilage and remove any affected produce.

Understanding Expiration and "Use-By" Dates

Not all fruits and vegetables will have tags on them. However, a few fresh produce items available in supermarkets or grocery markets have tags. These indicate some key indications for customers, which are:

  • “Best Before” Date: This specific data always indicates peak However, it doesn’t mean that the product in question is unsafe to consume after this date.
  • “Use-By” Date: This tag is specifically found on perishable items such as dairy and pre-cut For safety reasons, it usually indicates when the product should be consumed.
  • Visual and Sensory Checks: Analyse the texture, smell, and appearance before discarding produce.

Retain Freshness with Better Advancements

The best way to retain freshness in fresh produce is to use a combination of traditional and modern methods. Refrigeration, modified atmosphere packaging, and moisture control are some of the best methods to adapt to today. The many advancements in this field, such as AI-driven freshness tracking and biodegradable active packaging, will help further reduce food waste and retain the nutritional value of the produce.

Want to know more about fresh produce, how to retain their freshness and other agriculture- related tips and tricks?

About NICHEM

Long-standing Specialty Chemicals player with ISO 9001:2015 certification and a history of providing specialty solutions for over 25 years. The company is headed by senior chemical industry specialists with the combined expertise of more than 100 years. With an emphasis on eco-friendly, non-toxic products, the company’s primary strength is research, development,  and  customisation.  More  information  on  NICHEM  can  be  found at https://nichem.solutions

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