Course:FNH200/Projects/2024/Pickled Vegetables

Introduction

Pickled Food

Pickling is a time-honored method of preserving food, and can be divided into two kinds, fermented pickling and vinegar pickling. This technique not only extends the shelf life of food but also enhances its flavor. In this project, we will explore the rich history of pickling, the main production methods, and demonstrate the nutritional benefits and health impacts. Additionally, we will discuss packaging and storage methods, highlight Canadian food regulations related to pickling food, and provide guidance on home pickling techniques.

History

The history of pickles can date back to thousands of years ago, and according to historical relics and recipes, pickles were present in ancient Mesopotamia in the year 2000 B.C. By the mid of 1500 B.C, these vinegar-soaked vegetables had spread through the ancient worlds. Two historical figures were fond of pickles, one was the queen of Egypt - Cleopatra, she was credited to have pickles on a daily basis to increase skin’s firmness, the other one was the Roman Emperor Julius Caesar. He even fed pickles to the Roman army as one of long-term staple food supplies on the battlefield, a sort of salty snack containing the best natural electrolytes among non-synthetic beverages, which can effectively relieve muscle spasms and doesn’t have any gastrointestinal irritation, and thank to that, he achieved remarkable success.

There was a different way of preserving food called fermentation, it was found in ancient China. Traditionally, Chinese didn’t like to have raw fruits, so they fermented vegetables or fruits in salt or brine. Based on many historical documents, the Asian pickles and fruits (Pao Cai) we call today can actually be traced back to the 6th century B.C in ancient Chinese dynasties.

Production

Vinegar pickling, also known as quick pickling, involves immersing vegetables in a brine mixture created by heating water, vinegar, salt, and sometimes sugar. The key aspect of vinegar pickling is its 5% acidity, which not only preserves the food but also alters its flavor and texture. The choice of vinegar depends on the desired taste and appearance of the pickles. Distilled white vinegar and white wine vinegar are popular choices as they do not change the color of most vegetables. Another option is cider vinegar, which provides a milder flavor but tends to darken the vegetables .

The other method for pickling is fermentation. Vegetables are soaked in brine and fermented for weeks. Naturally occurring bacteria convert the sugars in the food into lactic acid. Lactic acid bacteria play essential roles during fermentation, producing diverse aroma compounds, bacteriocins, and exopolysaccharides, which contribute to key attributes of fermented pickles, such as improved texture, enhanced taste, and extended shelf life .  

For the preservation of both fermented and vinegar pickling, pasteurization and refrigeration are used to extend shelf life . One way to perform the low-temperature pasteurization treatment is to put the jars in a canner that is half-filled with warm water (120°F to 140°F). Heat the water and keep it at 180°F for 30 minutes .

Chemical Reactions

Acetic acid in pickling solution is an organic acid produced by fermentation, typically, fermented vegetables don’t add any vinegar, the acid is produced naturally. Lactic acid bacteria, which widely exist in natural environments and on vegetable surfaces, convert sugars into lactic acid and subsequently into acetic acid during fermentation. A sealed environment allows these bacteria to rapidly multiply, while salt inhibits the growth of harmful bacteria. Here are the chemical equation of acetic acid dissociation:

C₆H₁2O₆ → 2CH₃CHOHCOOH

CH₃COOH (acetic acid) → H⁺ + CH3COO^-

Vinegar pickling:

For vinegar pickling, the main difference from fermentation is that acetic acid is added directly into the pickle's initial process. It is an acid solution that exhibits low pH. Acetic acid is partially dissociated into hydrogen ion (h +) and acetate ion (CH3COO -) in water, which is the source of its acidity. Here is the chemical equation of acetic acid dissociation:

CH₃COOH (acetic acid) → H⁺ + CH3COO^-

Moreover, enzymes play a significant role in fermentation, enzymes are vital for breaking the sugar in vegetables into lactic and acetic acid, which enables the beginning of the fermentation process. In contrast, it is less important in vinegar solutions, an overly acidic or alkaline environment may inhibit enzyme activity or cause denaturation of the enzyme.

Packaging

The three main packaging methods of pickled vegetables are glass jars, plastic bags, and steel body cans. The pros and cons of each container is explained below.

Packaging Container	Pros and Cons
Glass Jars with Metal Closure	More resistant to corrosion and reaction with food constituents, preserving the texture and taste for a longer time. The transparency improves the visual appeal of the pickle inside. Recyclable and eco-friendly, a sustainable packaging option. The wide mouth gives a comfortable experience to access the pickles inside. Heavy and bulky, must be packaged with extra protection during transportation to prevent the physical damage of the glass.
Plastic Bags	Lightweight and easier to transport compared to the heavy glass jars. Durable. Able to withstand high pressure unlike glass jars. Cheap to produce in large quantities. Versatile. Can be easily designed into many shapes and sizes to fit the product. Not biodegradable. Have a negative impact on the environment. Not as shelf-stable as glass jars.
Steel Body Cans	Durable. Can withstand high temperature and pressure. Relatively lightweight. Suitable for long-distance shipment. Have a long shelf life. The process of canning requires high temperature. The consumer cannot see what's inside the cans. Can't be sealed again once opened.

Canadian Food Regulations

The Canadian regulations of food additives and chemical contaminants for pickled vegetables are listed in the following tables.

Canadian Regulation of Permitted Food Additives in Pickles
Additive	Maximum Level of Use and Other Conditions
Benzoic Acid	1,000 p.p.m.
Sorbic Acid	1,000 p.p.m.
Sulphurous Acid	500 p.p.m. calculated as sulphur dioxide

Canadian Regulation of Permitted Firming Agents in Pickles
Additive	Maximum Level of Use and Other Conditions
Aluminum Sulphate	Good Manufacturing Practice
Ammonium Aluminum Sulphate	Good Manufacturing Practice
Calcium Chloride	0.4%
Potassium Aluminum Sulphate	Good Manufacturing Practice
Sodium Aluminum Sulphate	Good Manufacturing Practice

Health Canada's Maximum Levels of Chemical Contaminants in Foods
Component	Maximum Level
Polysorbate 80 (polyoxyethylene 20 sorbitan monooleate)	500 mg/kg singly or in combination
Xanthan gum
Gum Arabic
Alginate (Ca, NH4, Na, K)
Propylene glycol alginate
Carrageenan
Calcium chloride, lactate and gluconate	250 mg/kg singly or in combination
Sulphur dioxide (as a carry over from raw product)	50 mg/kg
Benzoic acid and its sodium and potassium salts	1000 mg/kg singly or in combination
Chlorophyll copper complex	300 mg/kg singly or in combination
Riboflavin
Fast Green FCF
Tartrazine
Annatto extract
Sunset Yellow FCF
beta-Carotene
Oleoresin of paprika
Brilliant Blue FCF
Caramel, plain
Caramel (ammonium sulphite treated)
Tin (Sn)	250 mg/kg, calculated as Sn
Lead (Pb)	1 mg/kg

Home Pickling Methods

There are various methods for pickling food. The most basic method, quick pickling, involves packing fresh vegetables and spices into sterilized canning jars, pouring a vinegar-based pickling brine into the jars to submerge them, and then preserving the jars using the water bath canning method (boiling the jars in water).

The salt-brined method is suited for vegetables with a high water content. By placing the chosen vegetables in salt or soaking them in a salt-vinegar brine solution, water is drawn out of them. After the vegetables are sufficiently salt-brined, they should be rinsed and drained. Subsequently, the steps of quick pickling are followed.

To make fermented pickles, fresh vegetables need to be submerged in a salt-water brine inside a container that ensures the vegetables are not exposed to air or bacteria. The fermentation time depends on personal preference and environmental conditions; it typically ranges from days to weeks.

Ingredients & Nutrition 

Vinegar Pickling	Fermented Pickling
Great Value Baby Dill Pickles(1L)	T&T Kimchi (1kg)
Ingredients: cucumbers, water, vinegar, salt, spices(Mustard) and spice extract, calcium chloride, polysorbate 80, colour (tartrazine).	Ingredients: napa cabbage, radish, kelp stock (water, radish, dried kelp, dried shiitake mushrooms, salt), Sugars (pear purée, sugar, high-fructose corn syrup), red pepper powder, Sorbitol syrup, garlic, onions, salt, glutinous rice flour, monosodium glutamate & ginger, lactic Acid, seasoning, xanthan Gum
Dill Pickles Ingredients	T&T Kimchi Ingredients

Roles of Ingredients

Great Value Baby Dill Pickles

• Cucumbers: Primary ingredient.
• Water: Used in the brine solution.
• Vinegar: Act as a preservative, used to add acidity.
• Salt: Act as a preservative.
• Spices (mustard) and spice extract: used to add flavor of food.
• Calcium chloride: keep cucumbers firm and crunchy.
• Polysorbate 80: An emulsifier to keep spices evenly distributed.
• Colour (Tartrazine): Yellow food coloring for appearance.

T&T Kimchi

• Napa Cabbage & Radish: Primary ingredient.
• Kelp stock - Made from water, radish, dried kelp, dried shiitake mushrooms, and salt.
• Sugars (pear purée, sugar, high-fructose corn syrup): Add sweetness, aid for fermentation.
• Red pepper powder: Add flavor to the food.
• Sorbitol syrup: Act as a sweetener.
• Garlic, Onions: Enhance flavor of the food.
• Salt: Act as a preservative and aid for fermentation.
• Glutinous Rice Flour: Thickens the Kimchi paste.
• Monosodium Glutamate & Ginger: Enhance flavor.
• Lactic Acid: produced during fermentation process.
• Seasoning: Add flavors.
• Xanthan Gum: Act as a thickener and stabilizer.

Main Differences

Great Value Baby Dill pickles is a vinegar picking product, it is preserved with vinegar and salt. T&T Kimchi is a fermented pickling product, it is fermented with sugar, salt, and lactic acid bacteria, which is the microorganism to convert lactose to lactic acid in the food.

Health Impact

Pros

From the nutrition facts of the Great Value Baby Dill Pickles, it can be considered as a low-calorie snack since there are only 5 calories per 2 pickles. This food is also fat-free. It is beneficial for heart health since it does not contain cholesterol. Studies have shown that cholesterol can lead to a high risk of heart disease.

Cons

From the nutrition facts, these pickles contain a high amount of sodium, with 170 mg of sodium per 2 pickles (7% of the daily value). Research has shown that high sodium intake can contribute to high blood pressure and related cardiovascular issues. Furthermore, the presence of calcium chloride, polysorbate 80, and tartrazine might be a concern for people who might experience allergic reactions to these additives.

Pros

From the nutrition facts of the T&T Kimchi, it can also be considered as a low-calorie snack since there are 10 calories per 2 tbsp. This food is fat free. Furthermore,  Kimchi contains lactic acid produced from the fermentation process. Studies have shown that it helps to improve digestion of lactose and control of serum cholesterol levels.

Cons

One of the negative health impacts is that Kimchi contains 220 mg of sodium per 2 tbsp, which can also lead to high blood pressure and cardiovascular issues. The food product contains sugar. Although the overall amount of sugar is low, it can cause some health issues such as obesity.

Summary

It is clear that both fermented and vinegar pickling, as vegetables preservation methods, have not only enhanced flavor but also extend the shelf life. Pickling, as an ancient method of preserving vegetables, has a history that can be traced back to ancient Mesopotamia and China. Over such a long period of change, people have learned to use different ingredients and additives to create a variety of pickles. The packaging materials used for these pickles also vary widely. Packaging options such as glass jars, plastic bags, and steel cans each have their pros and cons, affecting the product's quality and environmental impact. However, the nutritional analysis of pickles is quite distinct for both fermentation and vinegar pickling. The most notable aspect is their low-calorie content but high sodium levels.

Final Exam Question

Which microorganism is used in the production of fermented pickles?

A. Acetic acid bacteria

B. Yeasts

C. Lactic acid bacteria

D. Propionic acid bacteria

Fermentation is a technique to produce pickled vegetables, and we learnt about it in Lesson 9. We choose this question because it ties our topic of research back to the lecture.