The Simple Kitchen Step That Improves Juice Extraction: What Happens Inside a Lemon When You Heat It for 10 Seconds?

Sometimes, a fresh lemon right out of the refrigerator may resist the squeezing process and yield juice unevenly. However, after placing the lemon in the microwave for some time, its softness increases. There is a scientific basis for this phenomenon. Plant cells are surrounded by a cell wall which makes up the firmness of the cells. Lemons are made up of pectin which is a carbohydrate molecule.

An article on ScienceDirect published on Carbohydrate Polymers states that pectin creates a matrix in the fruit by holding water, and this makes the fruit rigid. However, as soon as heating occurs, the bonds present in the cell wall start getting relaxed, thus making it possible for the liquid inside the fruit to flow freely.

Microwave heating plays a major role


Microwaving is different from other techniques as it directly heats up the water molecules present inside the fruits. From the studies conducted about microwave assisted extraction available at ScienceDirect, it is evident that such heating causes internal pressure buildup, which in turn facilitates cell structure destruction. With the help of heat generated from microwaves, there is internal pressure buildup, resulting in small cracks in the cells. The fruit cells become easier to break as pressure is exerted from outside. In contrast to conventional techniques, short-term heating does not deteriorate the fruit’s quality; rather, it maintains its chemical composition along with making it more usable.

Efficiency and waste reduction

Apart from its practicality, there are efficiency aspects associated with this approach. Studies have shown that increased efficiency in extracting juices results in minimized wastage through the optimal use of all parts of the fruit. In industry, the same concept is used in the recovery of pectin from citrus waste. In a domestic environment, there will be less juice wasted after the process in the rind and pulp of the lemon. Allowing the lemon to get some heat makes it easier to extract juice from it.