Desenvolvimento de um novo produto alimentar
: Pedras Granizado

  • Ângela Carina Azevedo Santos (Student)

Student thesis: Master's Thesis


This study was executed in one of the country’s major beverage production companies, “Unicer” in partnership with “Escola Superior de Biotecnologia” of Oporto from “Universidade Católica Portuguesa”.The study focused on the development of a new food product – “Pedras Granizado” in other words a slushy ice beverage from the brand “Pedras” based on the “Pedras Sabores Limão” lemon flavoured carbonated water. The intent was to produce a 100% natural beverage, without any added food colourings or preservatives that could be commercialized in liquid form and later be converted into a slush beverage by placing it in any household freezer for 10 minutes.“Pedras Sabores Limão” is a beverage that is essentially made up of naturally carbonated mineral water (100% natural), citric acid, fructose syrup, concentrated lemon syrup, and natural aromas. In agreement with Patent No. 3,826,829 from July 30th, 1974 - “Slush Beverage containing fine-grained ice crystals”, a slush beverage must include in its composition, approximately 80 to 85% water, and 15 to 20% solids, where the latter should consist of sugars, hydrocolloids, freezing point depressing materials (polyhydric alcohols or poly alcohols), citric acid and the desired aroma.With “Pedras Sabores Limão” as a starting point and based on the existing literature, we studied which ingredients needed to be added to the original formula in order to obtain the desired end product. Initially the beverage was reproduced with the exact ingredients in the patented formula, and then in the following stages, ingredients, as well as, different combinations of ingredients, were left out one at a time, in order to understand each of these contributions to the end product, whether it be to the beverage texture or to its production time.The conclusion reached was that there are two groups that have a positive effect on the slush beverage’s texture: the hydrocolloids and the alcohols. The hydrocolloids, particularly those that are thickening agents like pectin and guar gum, have a increased capacity for water retention that allows for a positive control of the size of the ice crystals, meanwhile the freezing point depressor materials (alcohols), display elevated viscosity in high water concentration and slowdown the freezing point, consequently allowing the formation of small ice crystals along a liquid matrix instead of an “ice block”, in other words, these groups confer and guarantee stabilizing properties to the end product. Due to the nature of the product and the proposed goal for its development, the nucleation agent calcium carbonate was added to the “Pedras Sabores Limão” formula and consequently it was possible to successfully obtain a slush beverage in one hour using a household freezer.
Date of Award11 Apr 2017
Original languagePortuguese
Awarding Institution
  • Universidade Católica Portuguesa
SupervisorConceição Hogg (Supervisor), Miguel Cancela (Co-Supervisor) & Cristina L.M. Silva (Co-Supervisor)


  • Drink
  • Innovation
  • Slush
  • Freezing


  • Mestrado em Engenharia Alimentar

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