Taste is one of the most important properties of food. It determines whether the product is a niche product and appeals to a small part of the population or whether it appeals to the masses. If the taste is not interesting, the chance for repurchase reduces significantly.
Next to taste, texture has been gaining popularity. Innova Market Insight indicates that texture claims have been growing as a percentage of newly introduced product as well as in absolute numbers all over the world with front label statements such as:
- - Crunchy
- - Smooth
- - Super Moist
- - Chewy
Sourness has been front and centre in sugar confectionery in Europe and North America for several years now, with Asia and Latin America starting to increase the sourness level in sweets. New product concepts introduced in Asia to the market vary from Sweet & Sour, Spicy & Sour to Extremely sour.
Candies have been inexpensive indulgence for a very long time. Although some confectionery products have nutritional benefits, most consumers will purchase and enjoy confectionery products for their sensorial sensation.
Taste, Texture & Stability
|Gelling Agent||pH Sensitive||Remarks|
|Gelatin (protein)||Limited||pH close to the iso-electric point will cause the structure to change, high pH will denature the protein (off odours).|
|Starch||Limited||Too long at low pH and high temperature will breakdown the starch.|
|Pectin||Yes||Optimal pH range is 3.2-3.6. Gelling/processing problems with a too high or too low pH.|
|Carrageenan||Yes||At a pH below 3.5, carrageenan is not recommended for use as a gelling agent as it will be unstable and degrade at high temp.|
|Gum Arabic||Yes||Less stable when pH is below 3.|
|Agar||No||Gels are formed independently of the pH.|
|Locus Bean Gum||No||Being non-ionic, locust bean gum is not affected by ionic strength or pH but will degrade at higher temperatures.|
|Xanthan||No||The viscosity of xanthan gum is stable at low pH values and at high temperatures for a long period of time.|
|Gellan gum||Yes||Maximum viscosity occurs at pH 6 but falls above pH 9 and below pH 4.|
In soft boiled confectionery or chewies/jellies, the texture and mouthfeel can be managed by ingredients (starch, protein, fat) and/or by additives. Most texturising additives that are used in the food industry are pH dependent, the mouthfeel and texture changes with different pH values (see table above).
In hard boiled confectionery the inversion (hydrolysis of sugar into glucose and fructose) causes candies to get sticky and lose their shape (deformation or cold flow). The stability of candies, especially in the challenged Asian environment (high temperature & high humidity) is greatly reduced by high levels of inversion.
Inversion heavily depends on:
- - pH
- - temperature
- - time
- - moisture content
Changing the pH in food in itself is not very difficult; maintaining the taste and texture is more challenging.
Sourness & pH
Although sourness is a taste, it can be used to create taste differentiation. The problem normally is that when the sourness is increased, the pH decreases. A lower pH in itself is not a big problem, but many processes change when the pH is changed.
Creating different sourness while maintaining the pH is quite beneficial for many food producers, the trick is to use buffered acids. Buffering an acid will stabilise the pH while increasing concentration will increase sourness.
The two graphs show clearly that with a buffered acid the pH will not reduce much but the sourness is increasing linear with the concentration. Further, it shows that buffered lactic acid can create a similar sourness as a non-buffered acid if about two times the amount is used, while the pH is higher than 3.0.
Sourness can be created quite easily for confectionery products with pH as high as 4.5, if the pH needs to be higher, buffering the acid might impart some saltiness or bitterness depending on whether sodium or potassium is used for buffering the acid.
Therefore, though sourness and pH are correlated, combining acids (e.g. citric & lactic or lactic and tartaric) can enhance the flavours and reduce the saltiness/bitterness with respect to buffering.