LIQUAM project uses high-power ultrasound to delay honey crystallisation without compromising nutraceutical elements

Honey contains natural vitamins, minerals and enzymes that give it anti-viral, anti-bacterial and anti-fungal properties. It is considered a good anti-oxidant and anti-inflammatory, which promotes digestive health, stabilises blood sugar, strengthens immunity and protects against respiratory diseases.

When extracted from honeycombs, honey is a semi-transparent viscous fluid, but within a few weeks its natural sugars, alongside air bubbles, cause it to crystallise – putting off consumers and risking fermentation.

“Pretreatment pasteurisation can delay crystallisation up to 12 months post-processing, but its extreme heat degrades the honey,” notes Estela Pacheco, LIQUAM project coordinator and cofounder of Sonicat Systems [1], the project host. The project team had already developed a patented technology (LIQUAM) for honey processing, and developed a minimum viable product (MVP) using high-power ultrasound (HPU). EU funding helped them to further optimise their innovation into a prototype – LIQUAM450.

“LIQUAM delays crystallisation, but because the process never exceeds 55 °C, honey’s liquid state is extended without compromising quality or nutraceutical attributes,” explains Iratxe Perales, Sonicat Systems co-founder.

Honey pasteurisation usually heats honey to around 80 ºC for 2-3 minutes, which melts sugar microcrystals. The honey is then flash-cooled to 45-50 °C. Being heat-sensitive, this process degrades quality, freshness and nutraceutical attributes.

“For example, the antioxidant capacity of raw honey is degraded by around one third,” says Perales. LIQUAM’s high-power ultrasounds alternate between low-pressure and high-pressure waves, forming millions of small vacuum bubbles which grow until they violently collapse, transforming the shock waves into mechanical effects which break down sugar crystals. This phenomenon, called acoustic cavitation [2], can be used at ambient temperatures.

The team installed an upscaled version of their LIQUAM450 prototype over five months in the industrial plant facilities of Adam Foods, Girona.

“Microscopic imaging confirmed that LIQUAM achieves crystallisation levels similar to pasteurisation, reducing it to 0.01 %. But crucially this did not significantly impact moisture, hydroxymethylfurfural and enzymes. These last two are important indicators of freshness,” notes Perales.

Pollen particles, used to identify honey’s botanical origin, were also not damaged, and the honey remained liquid for a time comparable to pasteurised honey. While the LIQUAM project enabled the team to further optimise their product – scaling up to industrial treatment rates, alongside testing and CE certifying their LIQUAM450 prototype – problems with sourcing components in the EU meant that a final assembly could not be completed on time.

“Our initial prototype processed 100 kilo-grammes per hour for €70,000, LIQUAM450 achieves this for €50,000. But increased material and component costs have driven up our commercial price. Also, LIQUAM450 needs three times more energy than our previous MVP did,” says Perales.  The team did however launch a product called Honey.AI [3] comprising a digital microscope, and using computer vision and machine learning to automatically analyse honey. This includes detecting different pollen types to accurately authenticate floral sources, providing results in under an hour. “We plan to offer this solution to the honey industry, creating potential leads for LIQUAM. We will also expand Honey.AI into an automatised pollen-analysis application,” says Pacheco.

LIQUAM helps stimulate sustainable food consumption, while promoting affordable healthy food. It also helps preserve and restore European ecosystems and biodiversity, bearing in mind that bees are responsible for about one third of crop production [4].

“LIQUAM also offers European beekeepers a means to add high value to their honey, differentiating it from low-priced imported foreign honey,” Perales adds.