FoodSHOTS Episode 3: Jams, fruit preserves and pectin

Summary

In this episode of Magic Maillard Maple, Tristan delves into the science of jam-making, exploring food preservation techniques such as using heat, sugar, and pectin. He demonstrates the process of making strawberry jam, highlighting the importance of sterilizing jars, adjusting pH levels, and ensuring the right solid content. The episode also touches on the chemistry behind gelling agents like pectin and how different preservation methods, like making jellies and fruit curds, can capture the flavors of summer year-round. It’s an informative and delicious journey into the science of food preservation.

Takeaways

• 😀 Jam making is a method of food preservation that helps prevent spoilage by inhibiting microbial growth and enzymatic changes.
• 😀 A surge in cream tea deliveries during the Covid-19 lockdown led to increased interest in homemade strawberry jam as part of the experience.
• 😀 Preserving food involves controlling spoilage caused by microbes, enzymes, and pests, while also maintaining nutritional value and safety.
• 😀 Common methods of food preservation include using heat, chilling, freezing, sugar, salt, drying, fermentation, and adding preservatives.
• 😀 The process of making strawberry jam involves boiling fruit and sugar, sterilizing jars, and adding pectin for gelling.
• 😀 Pectin, a natural gelling agent, is extracted from fruits like apples and citrus. It forms a gel that holds water, contributing to jam's texture.
• 😀 High methoxyl pectins are used in traditional jams, where sugar and low pH help pectin molecules crosslink to form a gel.
• 😀 To ensure successful jam-making, the pH of the mixture must be below 4, which helps inhibit microbial growth and assists with gel formation.
• 😀 A refractometer is used to measure the solids content of the jam. The required minimum for a product to be considered jam is 60% dry solids.
• 😀 To test if jam is set, a drop of the mixture is placed on a cold plate. If it forms crinkles as it cools, the jam is ready to be stored.
• 😀 Beyond jams, you can make jellies (from fruit juice), and fruit curds (emulsions stabilized by egg proteins) using different techniques and ingredients.

Q & A

What is the primary purpose of jam making?

The primary purpose of jam making is to preserve the fruits of spring and summer, allowing them to be consumed throughout the year.

How does food preservation prevent spoilage?

Food preservation prevents spoilage by preventing microbial growth, inactivating spoilage enzymes, and protecting the nutritional value of food.

Why is sugar important in the jam-making process?

Sugar helps jam to set by drawing water out of the fruit, lowering water activity, and allowing pectin to form a gel.

How can we check the pH of the jam mixture?

The pH of the jam mixture can be checked by stirring a small amount of the jam into water and using a digital pH meter or pH indicator strips.

What is the role of pectin in jam?

Pectin acts as a natural gelling agent, helping to form a gel by crosslinking in the presence of sugar and acid, trapping water within its structure.

How do high methoxyl pectins form gels?

High methoxyl pectins form gels by using sugar to reduce water activity and lowering the pH, which decreases electrostatic repulsion between the pectin chains, allowing them to crosslink.

Why do we need to check the soluble solids content in jam?

The soluble solids content needs to reach at least 60% to qualify as jam, and checking this ensures the proper consistency and texture for the final product.

What is the function of a refractometer in jam making?

A refractometer measures the bending of light through a liquid, allowing the user to determine the soluble solids content of the jam.

How do we test if the jam has set properly?

To test if the jam has set, spoon a drop onto a cold plate and tilt it. If the jam crinkles, it is ready and will set properly upon cooling.

What is the difference between jam and jelly?

Jam is made by boiling whole fruit or fruit pulp with sugar and pectin, while jelly is made from fruit juice, which is strained before boiling with sugar and pectin.