A balanced diet must fall within nutrient parameters (carbohydrates, fats, proteins) expressed as a percentage of the total caloric value, considering a limit to the same which depends on other factors (gender, weight, muscolar activity…).
As a matter of facts, 45/60% of the calories ingested should come from complex carbohydrates. 15% of calories should come from proteins, 20/35% from fats of which less than 10% from saturated sources. A food that is defined as balanced is such if it provides the right quantities of the nutrients mentioned above plus others such as minerals, fibers and specific amino acids. Without giving this introduction the rate of universal value or exhaustive character, it can be used as a starting point for the subsequent analysis.
It has long been debated whether Italian style ice cream can be a complete food (so that it can even be considered a meal replacement) but a quick analysis of its composition reveals some limiting aspects.
| Italian ice cream percentage | Relative caloric percentage | |
| Carbohydrates | 24% | 50% |
| Fats | 8% | 38% |
| Proteins | 3,8% | 8% |
| Kcal/100g | 190 |
White vanilla industrial “gelato” composition
If it is possible to reduce fats to 7% to align them to the maximum limits of the above scheme (approximately 35% of the total caloric intake) it is not possible to increase proteins to a value that satisfies a balanced intake using normally available ingredients, whose most concentrated protein source comes from skimmed milk powder.
From a rough calculation, the optimal protein value to make gelato a well-balanced food should be double of what is naturally present in standard recipes, i.e. 8%.
Reaching this value with skimmed milk powder is impossible due to the concentration of lactose that would result in a rapid re-crystallization of the same. Even the use of a delactosated SMP would influence the sugar composition resulting in an unsuitable product.
The dairy industry therefore provides some alternatives available such as concentrated (MPC) or isolated (MPI) milk proteins or whey proteins (WPC or WPI), with all their variants of denaturation, micro-particulation and hydrolysis.
Reaching 8% of milk protein value with concentrated sources of dairy derivatives in gelato/ice cream recipes implies rheological problems both in the liquid and frozen phases mainly due to excessive gelling or viscosity which may be reduced by acting drastically on the hydrocolloids and emulsifiers controlling fundamental parameters of the recipe.
This approach rarely gives the desired results, forcing, among other things, the execution of “real shelf life” tests without being able to rely on a database of “historical” results or extrapolative models for accelerated shelf life.
In the last two years, concentrated protein systems (80/82% protein value) have been developed for the industrial ice cream market by combining micellar caseins with MPC and WPC with medium and medium-high hydrolysis values. It has been demonstrated both at a laboratory and industrial scale that these protein mixtures allow the formulation of Italian style ice cream with the same combinations of hydrocolloids and emulsifiers as products with a standard protein value, thus allowing considerable ease of formulation which involves the replacement of the skimmed milk powder with the protein mixtures in question.
These combinations have several positive characteristics such as, first of all, the applicability to thermal processes at high temperatures (for example for ready-to-use liquid mixes for high protein UHT ice cream) or at normal pasteurization temperatures. The thermal process in itself does not affect the viscosity of the liquid product, making it available for homogenization processes and subsequent cooling without impact on the operating pressure if not due to the increase in total solids which, obviously, has some influence.
During the ageing processes, even longer than 10 hours, the total hydration of the solid ingredients does not drastically impact the general viscosity, maintaining the liquid product well pumpable and workable in continuous or discontinuous batch freezers.
As regards the overrun of the finished product (pre and post batching volume ratio), there were no difficulties in reaching values of 100/120% during the entire production, highlighting a consistency in maintenance during the production cycle similar to that obtainable with conventional ice cream.
The increase in protein to 8% has an impact, although not drastic, on the taste of the product, but nothing that cannot be completely fixed with the addition of a natural flavoring phase.
Summarizing the above, a probable interaction between caseins and hydrolyzed MPC/WPC allows to obtain non-cross-linked systems with extremely improved results for the application of micro-particulate whey protein mixtures from the point of view of the viscosity of the liquid medium. The strong point of this application is the possibility for formulators to rely on data acquired regarding the hydrocolloid phase to be applied, without opening research projects that are often complex and uncertain.
The application of such protein mixtures in milk-based recipes, perhaps in parallel with those specific for sorbets (read my blog “the use of transparent whey protein hydrolysates in popsicles and sorbets”) can give a better nutritional aspect to a product category, Italian style ice cream, often considered of secondary importance for nutrition. The possible claim on the label would be “source of protein”, exceeding 12% of calorie content of protein origin.
However, if you want to declare the finished product “high in protein” where the caloric intake of proteins must be at least 20%, it has been experimentally found that the best solution is to raise the protein level to around 10/11% and reduce the caloric intake of fats bringing them to 4%. In this way, the 20% caloric contribution derived from proteins is exceeded on the total amount provided by the food without any negative impact on structure.
