Innovative citrus fibers can increase yields, reduce syneresis and retain moisture in various applications
by Brock Lundberg, President of R&D, Fiberstar
(March 17, 2016) Today, technologies are introducing new hydrocolloid types, which are capitalizing on the clean label story. However, the challenge is identifying an economically viable process that can produce a dried product that can be stored, transported and rehydrated to form a product that functions like the pre-dried product. As a result, a new patented processing technology proved to be successful by producing a commercial natural citrus fiber called Citri-Fi that can be activated during hydration. Because this citrus fiber is made using a mechanical process without chemical modifications, it is considered natural. This fiber type is stable in a range of harsh pH and temperature conditions. Moreover, this technology produces citrus fibers that are neutral in color, taste and odor. Because of its high surface area, these citrus fibers can be used in various applications, due to its high water holding capacity and oil binding properties. For instance, these citrus fibers increase yields, reduce syneresis and retain moisture in baked products, meats, dairy products and dressings.
A plot showing the relationship between the viscosity of processed citrus fiber versus temperature is shown in figure 1 for pH values of 7 and 9. The solutions were prepared at two different pH values and heated to the indicated temperature followed by viscosity measurement. At pH 7, there is the lowest amount of viscosity drop with increasing temperatures. This compares to more purified hydrocolloid forms that tend to have a more significant viscosity drop with increasing temperatures.
Water holding capacity (using AACC 56-30) and swelling capacity for the various particle sizes were determined as a measure of this citrus fiber’s hydrophilicity, which is shown in figure 2. The reason for following the AACC 56-30 method is because the citrus fiber contains various levels of soluble components, which would be lost using other water holding capacity methods that discard the supernatant. The water holding capacity and swelling capacity results show only a small change as particle sizes change, which indicates that the citrus fiber’s attraction to water is due to hydrogen bonding with water on the internal surface of fiber as it expands, rather than hydrogen bonding limited to the external surface of the fiber.
Lastly, this patented process produces a highly, natural citrus fiber with a unique composition containing soluble and insoluble fiber and protein. Due to the intact pectin still present, low pH and high sugar conditions can activate gelling properties which are beneficial when replacing/reducing added pectin. Studies at a German University demonstrated pectin replacement in bakery fillings, fruit spreads and fruit preparation in stirred yogurts. These novel functionalities using natural byproducts are advances the industry will rely on as commodities fluctuate in price, supply and regulatory status.