Reassessing the Impact of Pasteurisation on Juice & Smoothie Quality
The benefits of pasteurisation on the safety and shelf life of fruit and vegetable juices and smoothies are well proven. While thermal processing can occasionally have unwanted effects on product quality such as nutrient loss and changes in colour, flavour and texture, a recent study has suggested that pasteurisation can aid digestibility. With this in mind, is it time to reconsider how we choose the best pasteurisation method for juices and smoothies?
Consumers around the world are now well aware of the benefits of eating fresh fruit and vegetables, and over the last two decades, juices and smoothies have become a convenient and tasty way of boosting uptake.
Worldwide, juices have the highest purchase penetration among soft drinks, with 57% of consumers purchasing juices, juice drinks and smoothies in the past year. New products and brands continue to be developed and launched by both large multinationals and local specialist producers, with functional claims and nutritional ‘shots’ among the latest developments. Mordor Intelligence predicts that the global smoothie market will reach US$25.21 billion by 2031 (compared to US$16.65 bn today).
Within this market, ‘fruit-based smoothies hold a 55.72% market share, leveraging established supply chains and consumer familiarity. Plant-based smoothies are growing rapidly, with a 9.65% CAGR projected through 2031 while vegetable-based smoothies present opportunities for differentiation with functional positioning and unique flavours.’
Over the last 20 years, high-pressure processing (HPP) has been adopted by some manufacturers in an attempt to extend the shelf life of their products while retaining their taste, colour, and nutritional value (in particular vitamin C content). However, the effectiveness of this approach varies with product. For example, studies have shown that while the technique may improve the perception of orange juices, it can have a negative effect in the case of apple juices.
While the aim of both thermal and pressure pasteurisation is to reduce the number of harmful bacteria and enzymes present, other studies have also suggested that pressure-treated smoothies lose more compounds and nutrients (such as phenols and carotenoids) during storage than heat-treated ones. Not only that, but a more recent study has shown that ‘processing smoothies with high heat could also make polyphenols easier for the gut microbiome to absorb.’
Manufacturers need to be as efficient as possible in their production to maximise profits. They also need to choose equipment which preserves the physical characteristics of their product to reduce wastage.
Many fruit and vegetable products need to be handled delicately in order to avoid splitting or shearing, while careful temperature control is also required to avoid the creation of undesirable flavours. It is also often necessary to process high viscosity products without fouling, or to preserve any particles in the product without damaging them. Corrugated tube heat exchangers or scraped surface heat exchangers are ideal for pasteurising high-quality juices and smoothies without damaging product integrity.
For the simplest fluids, corrugated multi-tube designs such as the HRS MI Series and the HRS MR Series are suitable. As materials become more viscous or complex, the range moves through corrugated tube-in-tube or annular space designs such as the HRS DTA or HRS AS Series respectively. For the most viscous or delicate materials then scraped surface heat exchangers such as the HRS R Series or HRS Unicus Series are ideal.