What Is Annealing (ANN)?

ANN is the process of altering starch by heating it in excess water at a temperature between the starch gelatinization temperature and the glass transition temperature, with times ranging from minutes to days. The ANN process causes reorganization of the starch molecules and regular arrangement of the double helix structure of amylopectin. The ANN conditions vary greatly in different reports, which have a great effect on the starch obtained.

Table 1. Different annealing conditions in different reports. (Fonseca, et al., 2021)

Advantages of Annealed Starch

ANN treatment changes the physicochemical characteristics of starch without damaging the structure of starch granules. In general, the higher the ANN temperature is, the more obvious the change in starch structure and functional characteristics can be seen. The technology is suitable for starch with large amorphous regions because the heat required for gelatinization is inversely proportional to the crystalline area of the starch.

Fig.1 Influence of annealing on the double helix structure in starch granules. (Vamadevan, et al., 2013)

Annealing (ANN) Service

As a conventional physical modification method of starch, ANN has been widely used in practical production. CD BioGlyco has an absolute advantage in the production and technology development of modified starch, and we guarantee to provide customers with high-quality annealed starch.

• Morphological properties
  ANN has little influence on the appearance of starch, and may increase the surface porosity and pore size of some starch types.
• Pasting properties
  The associations among the chains in the amorphous region of the starch granules and the crystallinity are increased, the resistance to high temperature is improved, the retrogradation is weakened, and the pasting properties are improved by ANN.
• Solubility and expansibility
  ANN results in an increase in the interactions of amylose and amylopectin molecules, a strengthening of the bonds, a more stable structure, and increasing crystallinity, which reduces the expansibility and amylose leaching of the starch, thereby improving the quality of starch pastes and gels applied in food.
• Crystallinity
  ANN improves the crystal perfection of starch granules, while the crystallinity of amylose is not affected.
• Thermal properties
  ANN extends the gelatinization temperature range and reduces the gelatinization enthalpy of the starch, which expands its application in foods that are exposed to high temperatures during production.
• Enzymatic digestibility
  Starches of various types and from different sources show different influences on enzymatic digestibility.

Publication

Technology: ANN

Journal: Food Hydrocolloids

IF: 10.7

Published: 2017

DOI: 10.1016/j.foodhyd.2016.08.006

Background: ANN has been widely concerned for its chemical safety, low cost, and environmental friendliness, which can greatly change the functional characteristics of starch. Due to the complexity of the mechanism, it is necessary to further study the changes in starch properties caused by ANN. The sensitivity of starches with A-, B-, and C-type polymorphs to ANN was studied, which provides a new idea for the study of the specific ANN mechanism.

Results: In wheat, yam, and potato starch, ANN temperature lower than starch gelatinization temperature had no significant effect on starch granule morphology and the long- and short-range ordered structure, indicating no new-formed double helix structure during the process. It is further speculated that ANN enhances the stability of the starch structure by increasing the association of starch chains. Due to the long- and short-range ordered structure, the resistance to heating and shearing annealed starch increased, which greatly improved the paste viscosity of potato starch.

Fig.2 Morphological comparison of native and annealed starch granules. (Wang, et al., 2017)

Applications

• Noodle production. Annealed starch reduces cooking losses, and improves the texture properties and the taste of cooked noodles.
• Corn starch/corn oil/lysine blends production
• Nanoparticle study and production

Highlights

• Continuous and large-scale production methods
• Environmentally friendly production process
• Combined starch modification

CD BioGlyco offers a variety of Starch Modification Services to assist you maximize the value of your starch. Except for ANN process, we also offer other Technologies for Starch Modification, such as Pre-Gelatinization, Heat-Moisture Treatment (HMT), Non-Thermal Physical Modification. If you are interested in our Starch Manufacture Service, please feel free to contact us for more information.

• Pre-Gelatinization
• Heat-Moisture Treatment (HMT)
• Cold Plasma Treatment
• Non-Thermal Physical Modification