Interactions between a Tree Exudate and a Loquat-Seed Starch

Fatin Chowdhury ’20

Figure 1: Researchers studied the addition of gum karaya to starch. Gum karaya is a substance that is harvested in India’s tropical environment.

As naturally derived ingredients become more sought after in manufacturing and other areas, the science behind biodegradable material continues to expand. Recently, in order to better understand the chemical dynamics of different ingredients in biomaterials and explore the possibility of developing an edible film, a pair of scientists located in South Korea investigated the interactions of a tree-based gum with loquat-seed derived starch. 

Initially, starch-rich loquat seeds were enriched with oregano essential oil. Because essential oils are hydrophobic, synthetic emulsifiers are sometimes added to solutions to promote material homogeneity, despite potential drawbacks such as human health risks. As such, the researchers were interested in investigating naturally derived gum karaya (GK) as a potential stabilizer for emulsion processes. The influence of GK on the film’s physical, thermal, and optical characteristics was determined via techniques such as tensile strength measurements and colorimetry/spectrometry-based analysis. Additionally, disc diffusion illustrated how active pathogenic bacteria were within the films. 

Tween 80, also referred to as polysorbate 80, is a liquid surfactant common in cosmetic and food industries. The purpose of this particular emulsive ingredient is to inhibit bacteria growth. GK was compared to Tween 80, and there was no difference found in the bioactivity of films based on whether they were treated with GK or Tween 80. However, when utilized at 15% and 20% concentration levels, GK led to increased biofilm tensile strength. As such, the researchers were able to conclude that gum karaya (GK) could be utilized as an alternative to Tween 80, due to the observed stability of the GK-starch combination. 

As the starch-based material industry grows and biofilms begin to be used for food packaging and biodegradable medical applications, it is important to comparatively inspect the bioactivity of related materials such as Tween 80 and GK in these kinds of products. Through these types of studies, it is possible for products to be more stably formulated and better suited for direct consumer usage. 



  1. T.L, Cao, et al., Effects of gum karaya addition on the characteristics of loquat seed starch films containing oregano essential oil. Food Hydrocolloids 97, 105198 (2019). doi: 10.1016/j.foodhyd.2019.105198.
  2. Image retrieved from:

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