Orange juice is often in the limelight, frequently falling on both sides of the health debate. Some claim the sugar content is too high to be regularly consumed, and yet the drink is still touted as one of the easiest ways to get vitamin C, or ascorbic acid, into our diets.

It has long been thought that much of the vitamin C content in orange juice is destroyed during the pasteurisation process, which most fruit juices undergo to kill off any pathogens present.  For many of those who were already sceptical about orange juice’s health credentials, the pasteurisation concern has been a tipping point, driving them away from juice as a whole.

However, a study led by food processing and packaging company Tetra Pak, titled ‘Vitamin C retention in orange juice production: Getting past the myths and doing more with less’, has established that vitamin C levels in orange juice are in fact barely affected by pasteurisation.

Pasteurisation misconceptions

“Elevated temperature breaks down vitamin C,” explains Tetra Pak sub-category manager for juice, nectars and still drinks Maria Norlin. “However, for standard juice pasteurisation the time the juice spends at an elevated temperature is very short, and the effect on vitamin C, as our study shows, is negligible.” In fact, the study suggests that the vitamin C drop off as a result of pasteurisation is as low as 2%, and even this number is statistically insignificant, due to variations in analysis methods.

The misconception that pasteurisation causes a drop in vitamin C levels is nothing new. In fact, Norlin believes that most people pick up the notion in childhood, when learning how to cook. “During traditional boiling of vegetables, potatoes and so on, there are significant losses of vitamin C. The food is exposed to 100°C for 10-20 minutes, which therefore breaks down vitamin C. During the boiling, vitamin C also leaches out from the food, into the boiling water.” While many assume the process is the same for pasteurisation, in reality the concepts are very different.

On the industrial side, Norlin describes how producers often associate degradation with pasteurisation due to measuring vitamin C levels later in the production process. The Tetra Pak study shows that vitamin C retention is actually affected by the amount of dissolved oxygen in the product, rather than thermal treatment.

The findings from Tetra Pak’s study have been published in the latest edition of its ‘Orange Book’, a guide to orange juice production and the surrounding industry.

Alongside the vitamin C pasteurisation discussion, the book also looks at high-pressure processing pasteurisation, a rapidly expanding facet of the industry. Another of the company’s studies published in the book highlights the benefits of lower pasteurisation temperatures, reducing energy costs while maintaining food safety levels.