How does High-Pressure Processing affect the sensory quality of fruit juices and smoothies?
Introduction
Fruits and vegetables have been
considered necessary in the human diet and are often called ‘protective foods.’
However, they are susceptible to losing quality since some are seasonal, and
some have a shorter shelf-life. Various processing methods have been
implemented to increase their shelf-life; thermal methods are the most common. However, this method
often deteriorates the quality of fruit-based beverages and affects their
sensory characteristics like taste, colour and flavour. Nutrient loss was also
observed using traditional methods of beverage processing. Therefore,
innovations in beverage processing techniques were made. High-pressure processing (HPP) is one such innovation
that is rapidly gaining popularity [1].
HPP achieves the effects of
pasteurisation without heating, and its effects on macromolecules and flavour
compounds are significantly lesser than thermal processing. In addition,
studies have shown that HPP preserves the aroma of fresh fruit juices, making
them highly acceptable among consumers. Therefore, the beverage industries seek to incorporate
HPP in fruit juice processing.
Studies focussing on the
effect of HPP on the sensory perception of beverages
A study was conducted by Song
et al., determining how the processing technique impacted the sensory profile
of orange juice and apple juice. Thermal- and High-pressure processing
techniques were used in the fruit beverages, and the sensory testing was carried out
among sensory panellists and consumers. It was noted that the temperature, time
and treatment significantly influenced the sensory profile of the juice. In the case of orange
juice, high-pressure processing was associated with visible fruit pulp, real
fruit juice flavours and fruit pulp mouthfeel. In contrast, HPP was associated
with a yellow-brown colour and cloudy appearance in apple juice. However, the
flavour profile was better in HPP-treated orange and apple juice, making them
more acceptable among consumers [2].
Sarantakou et al. studied how
the quality of avocado puree-based smoothie was affected by HPP, thermal
processing and no processing. Polyphenyl oxidase (PPO) is an enzyme which
causes browning in avocados. The study revealed that High-Pressure Processing
inactivates PPO, and treatment using the optimum pressure for a stipulated time
resulted in the smoothie being more ‘Fresh-like’ avocado characteristics with a
bright green colour, creamy texture and a natural avocado flavour. In addition,
avocados processed using HPP also had a higher retention of Vitamin C, implying
that HPP can be used as a non-thermal processing method that retains the
quality of avocado smoothie [3].
A comparison of the processing
of mango smoothies was conducted by Bi et al. It was observed that the smoothie
treated under a fixed pressure did not significantly increase the viscosity of
the smoothie, making it more ‘fresh-like’ and increasing consumer
acceptability. Also, this pressure led to the least deterioration in total
carotenoid content, making the smoothie more visually appealing among consumers
[4].
Another study was conducted on the effect of HHP
on a fermented pomegranate beverage. It was observed that the antioxidant
content was increased in HHP-treated beverages. In contrast, the content of the natural colour, anthocyanin, was
retained, unlike thermally processed beverages, where there was a deterioration
of the colour. However, no difference in taste was noted [5].
Guires Food research lab Fruit Juice Processing
The above studies indicate that High Pressure
Processing or HPP of fruit juices and smoothies was associated with colour
retention, better mouthfeel and taste. However, the pressure for processing the
fruits were different and one cannot say that a fixed measure of pressure
applied yield the same results for all fruits.
Conclusion
Fruit juices and smoothies
treated with the High-Pressure Processing technique retained colour and had
more natural flavour than thermally processed ones. In addition, they
can also give rise to a smoother mouthfeel. However, it is crucial to note that
the pressure values and time differ depending on the type of beverage
formulated and the fruits used, and the beverage formulators must be cautious
in using HPP.
How
the Food Research Lab can help
The Food Research Lab is a
global contract R&D facility that offers beverage formulation services for clients
worldwide. The Lab has a team of experts who assist with choosing the right
ingredients, developing a high-quality beverage with excellent sensory
characteristics and product labelling that complies with international
regulations, ensuring the product formulated is successful.
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