The ingredient, with worldwide production estimated at 35,000 tonnes a year, is currently widely used as gelling agents in jams, confectionary, and bakery fillings, and stabilisers in yoghurts and milk drinks.
The functionality of the pectin is dictated by the chemical fine structure, and the majority of the pectins used currently come from citrus peel and apple pomace.
"Other potentially valuable sources remain largely unused because of certain undesirable structural properties," said the authors of a recent review of research.
But advances into the structure and functionality of pectin could open the door to designer pectin from different sources with tailored functionalities, according to William Willats from the University of Copenhagen, Paul Knox from the University of Leeds, and Dalgaard Mikkelsen from Danisco in the journal Trends in Food Science and Technology (2006, Vol. 17, pp 97-104).
As such, the scientific literature lists numerous studies looking at alternative sources, ranging from sunflower seeds, potato peel, banana, cocoa husks, mango peel, pumpkin, and ambarella peel (also known as golden apple, Spondias cytherea). The latter was reported to be comparable to pectin from lime.
But will such sources ever rival citrus and apple?
For the moment, the industry thinks not: "Real alternative sources for pectin production do not exist," said Hans-Ulrich Endress, the secretary general for the International Pectin Producers Association (IPPA).
So why are people looking? One driver is the fruit processors themselves. "Pectin is in everything, all fruit and vegetables, so if you take the angle of the fruit processor, it is not surprising that people are looking at alternative sources to add value to their by-products," said Pierre Perez, product director of food gums for CP Kelco. "But when you ask the questions: What kind of yield does it give, and what is the pectin content, the maths very quickly tells you there is no future."
Dennis Seisun from IMR International, a consultancy that publishes the Quarterly Review of Food Hydrocolloids, agrees: "The issue with alternative sources is extracting pectin in commercially viable volumes."
With the price of hydrocolloids increasing, and pectin no exception, there exists a financial incentive to explore alternatives. Other reasons are given for searching for alternatives, including innovative or interesting functionality, or sourcing issues. But with citrus pectin, the ingredient is a by-product of the fruit juice, and lemon and orange oil industry.
"These have a large and steady production," said Perez. "But supply is currently impacted by a fast rising demand for fresh fruit, which is tightening availability."
So how much pectin does a lemon produce? According to Perez, a 200 gram lemon roughly breaks down into 100 grams of juice/oil and 100 grams of wet peel. "From 100 grams of wet peel, we can obtain roughly 15 grams of dry peel, which contains typically three grams of pectin," he said.
Ralph Appel, the business unit leader at Cargill Texturizing emphasises that apple and citrus will continue to dominate. "As both types have excellent but slightly differing qualities, between them they can meet the needs of our customers," he said.
Appel added that Cargill does have dedicated R&D to "continuously looks to advance our product range... At the moment, however, citrus and apple-based pectins provide the best quality gels and functionality."
Sugar beet crashing the citrus/apple pectin party?
Despite the continued dominance of citrus and apple, one source attracting attention is sugar beet. Willats, Knox, and Mikkelsen described it as: "Potentially an abundant and low cost source of pectin, but [it] is rarely utilised because its high degree of acetylation adversely affects functionality."
Appel concurred: "In terms of other pectin sources sugar beet pectin has an even greater number of 'hairy elbows' or non-galacturonic side-chains, which make it less easy to use than citrus peel or apple pomace, and while it doesn't gel it does offer other interesting functionality."
It appears that sugar beet pectin is making a small but important contribution. "Sugar beet pectin is mainly used for flavour oil emulsions but this is a small application," said the IPPA's Hans-Ulrich Endress.
"It is early days for sugar beet pectin," said Dr. Steve Bodicoat, marketing and innovations director for CP Kelco. "It works well where you have hydrophilic and hydrophobic components, and sugar beet pectin has an emulsifying effect."