Preserving food was traditionally done to extend access to vegetables and fruits outside their growing season when they were available in larger quantities than could be consumed before getting spoiled. It also prevents food waste and makes available a wide variety of foods throughout the seasons.
From spring to fall, it’s always something in season that’s worth preserving, from fresh asparagus, nettles, strawberries or apricots to cucumbers, tomatoes, peppers and cabbage.
Proper food preservation means maintaining its quality and nutritional value, plus appropriately sealing it to prevent contamination by pathogens or chemicals.
From the many classic and modern methods of food preservation, the most commonly used are:
- Dehydrating
- Pickling
- Canning
- Freezing
- Fermenting
All of them have pros and cons, but from a health standpoint, the best ways to retain and even enhance the nutrition profile of foods for longer are fermentation and freezing.
Fruits and vegetables are at their peak of tenderness and sweetness when harvested at the right time and perfectly ripen. They should be preserved or used immediately to take advantage of their highest phytonutrient, vitamin and mineral content.
Freezing
Freezing is by far the easiest way to conserve the goodness in fresh produce. It comes in really handy for fruits since they do not need any other preparation than washing, dicing and maybe sprinkle some lemon juice to prevent browning. Veggies, however, have to be blenched (i.e. green beans, peas, broccoli) or cooked (pumpkin) before freezing.
Advantages
* Convenient, fast and easy
* Preserves nutrients
* Easy to grab and use food
* Saves time with meal planning
* Allows precooking done in advance
* Lower carbon footprint than fresh veggies
Disadvantages
• Some fruits and vegetables that are higher in water will become mushy when thawed, as their cell walls break due to the water expanding when frozen. However, they’re great for smoothies or baking.
• Freezer burn can occur if packages have either not been airtight-sealed or kept frozen for too long.
• In case of a power outage longer than a few hours, some food may have to be discarded.
• Space restrictions: additional freezer may be needed.
What the science says
- Use the proper way to freeze, pack and store, and consume within 8-10 months, depending on the product.
- Boiled frozen vegetables such as green beans and zucchini have a better or equal nutritional value when compared with boiling fresh ones.
- There is more nutrient loss in fresh produce stored at 4°C for 7 days than in frozen vegetables over 12 months.
Fermentation
Humans used fermentation for thousands of years as a way to preserve foods, starting with alcoholic beverages, followed by cheese, tempeh, miso, sauerkraut, etc.
A particular type of fermentation specific to vegetables and dairy is lactic acid fermentation, named after the primary organisms involved, lactic acid bacteria, present in most vegetables and dairy.
This fermentation is done in brine (or milk) in the absence of oxygen. During the process, the lactic acid bacteria diffuse from food into the brine making it more acidic. As sugars are released, the bacteria multiply fast, and pH further goes down, creating a hostile environment for spoilage microorganisms.
These ensure the longer-term availability of your fermented products such as kimchi, cucumbers or yogurt.
Advantages
* One of the most economical techniques to preserve and process food
* Many health benefits due to increase of the nutrient content
* Natural source of some B-group and K vitamins
* May eliminate the need to supplement some vitamins
* Reduce food waste
Disadvantages
• Histamine intolerance – sometimes the human body cannot produce sufficient enzymes to digest the high histamine levels present in fermented products.
• Some people may not appreciate the sour or umami taste specific to fermented food.
11 Health-promoting effects of fermented foods and beverages
1. Increase probiotic activity, supporting the residential bacteria to enhance our immune function, digestion and absorption of nutrients.
2. Improve the digestibility of proteins in pulses (beans, lentils, etc.)
3. Provide a natural source of antioxidants, such as phenolic compounds and folates that protect against oxidative damage involved in most age- and diet-related chronic diseases.
4. Produce natural folate, important for red and white blood cells formation in the bone marrow and healthy cell growth and function.
5. Reduce stress responses and symptoms of depression or anxiety by producing the neurotransmitters involved in mental health – check out Understanding The Gut-Brain Connection
6. Support bone and cardiovascular health, due to the high content of vitamin K (i.e. kimchi).
7. Lower cholesterol levels by the action of the short-chain fatty acids (SCFA) produced in the process of dietary fibre fermentation.
8. Anti-hypertensive.
9. Anti-diabetic properties (i.e. sourdough bread, which has a low/medium glycemic index.)
10. Anti-allergic
11. Lower the anti-nutrients such as phytates in grains and legumes.
Fermentation not only improves the nutritional properties of vegetables, fruits, cereals, legumes, milk, fish or meat, but it also has a positive impact on human health.
Conclusion:
Preserving foods, especially fermentation, has additional health benefits (digestive, cardiovascular, bone health) beyond giving you access to products otherwise available only for a limited time.
References
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