Recrystallisation is defined as “any change in number, size, shape… of crystals” (Fennema, 1973) and basically involves small crystals disappearing, large crystals growing, and crystals fusing together, all of which result in an overall increase in ice crystal size. The crystals that form at the cold barrel wall are then scraped off by the rotating scraper blades and dispersed into the centre of the barrel where warmer mix temperatures cause some crystals to melt and others to grow and undergo recrystallisation. As the refrigerant absorbs the heat in the mix, a layer of water freezes to the cold barrel wall causing rapid nucleation (the birth of small ice crystals) (Hartel, 2001). Upon exiting the SSF, the ice cream, at about -5☌ to -6☌ (23☏ to 21.2☏) and with a consistency similar to soft-serve ice cream, undergoes static freezing where it is hardened in a freezer without agitation until the core reaches a specified temperature, usually -18☌ (-0.4☏).ĭuring dynamic freezing, the ice cream mix is added to the SSF at between 0☌ and 4☌ (32☏ and 39.2☏). Ice cream is frozen in two stages, the first being a dynamic process where the mix is frozen in a scraped-surface freezer (SSF) (an ice cream machine) whilst being agitated by the rotating dasher, a mixing device with sharp scraper blades attached, to incorporate air, destabilise the fat, and form ice crystals.

To control ice crystal size, it is important to develop an understanding of ice formation (known as crystallisation) during the freezing of ice cream. specific effects on ice crystallisation, and 2. Sweeteners influence ice crystal size by two main mechanisms: 1. If many crystals are large, the ice cream will be perceived as being coarse or icy. Smooth and creamy ice cream requires the majority of ice crystals to be small. In general, increasing the sweetener level increases creaminess as a result of the reduction in the size of ice crystals. Because perception of the sugars in fructose-only or HFCS-sweetened ice cream decays faster than sucrose, these sweeteners are said to enhance the flavours of fruits and spices that are masked to a degree by sucrose (White, 2014).īelow is a profile of sweetness response, from Hull (2010).īesides enhancing sweetness and flavour, nutritive sweeteners also determine textural creaminess and mouthfeel (Stampanoni, 1993 Guinard et al., 1997). Its perceived sweetness lasts for longer than that of fructose, but less than that of sucrose (Hull, 2010). Dextrose is less sweet than either fructose or sucrose. Fructose has a very intense sweetness that only lasts for a short period of time. The sweetness perception profile of High Fructose Corn Syrup (HFCS) is the sum of those of its constituent sugars, fructose and glucose (dextrose). If used in excess, its broad sweetness profile can mask flavours that are perceived at the same time. Sucrose imparts a sweetness that is slow to develop and slow to decay. Fructose, which has a relative sweetness value of 173, is the sweetest nutritive sweetener, whilst maltodextrins, having a relative sweetness value of between 6 and 17, have a bland taste with very little sweetness.īelow is a table showing the characteristics of sweeteners in ice cream, from Goff & Hartel (2013).Īs well as having different sweetness values, sweeteners also differ in the way that their sweetness is perceived. Sucrose is used as the standard and has a relative sweetness value of 100. Relative sweetness is a means of ranking sweeteners in comparison to one another.

Sweeteners differ in their relative sweetness. Lack of sweetness produces a flat taste too much tends to mask desirable flavours (Goff & Hartel, 2013). The main function of sweeteners is to increase the acceptance of ice cream by making it sweet and by enhancing the pleasing creamy flavour.

The primary purposes for using sweeteners in ice cream are: to provide sweetness and enhance flavour to develop smooth and creamy texture to make ice cream softer and easier to scoop and to contribute total solids. Because these sweeteners contribute metabolisable energy to the diet, they are called ‘nutritive’ or ‘caloric’ sweeteners. The most common choice of nutritive sweetener is a combination of sucrose (10-12%) and CSS (3-5%) (Goff & Hartel, 2013).īelow is a table showing suggested mix compositions for ice cream, from Goff & Hartel (2013). Sweeteners used in ice cream include cane and beet sucrose (‘sugar’), invert sugar, Corn Starch Hydrolysate Syrup (CSS), high maltose syrup, fructose or high fructose syrup, maltodextrin, dextrose, maple syrup or maple sugar, honey, brown sugar, and lactose.

Tiny balls ice cream