Laboratory Report Guidelines Components of the report Contents 1. Introduction (Title, objective/aims and background information) It presents relevant background with explanation on the focus of the...

VISCOSITY OF FRUIT JUICE (MANGO & ORANGE), HONEY & TOMATO SAUCE
Objective:
Rheological properties of food materials are very useful in their processing and storage processes because viscosity is an important physical property that correlates with other physicochemical and sensory properties.At a molecular level, viscosity is a result the interaction between the different molecules in a fluid. Viscosity will determine the energy required to make a fluid flow. The Brookfield Dial Reading Viscometer measures fluid viscosity at given shear rates.
Principles:
All fluids show a resistance to flow, called viscosity (η). Empirically, mobile liquids like water have a low viscosity whereas liquids such as thick oils have a high viscosity and flow only with difficulties.
Newtonian liquids show a constant value of viscosity as a function of shear rate (rate of deformation) but the viscosity is temperature dependent.
For non-Newtonian liquids, the viscosity remains constant at a fixed, maximum value at low shear rates, but at higher values ‘shear thinning’ is observed with subsequent reduction in viscosity. Non-Newtonian liquids are also known as Pseudoplastic.
Materials:
Commercial Fruit Juice, Honey & Tomato Sauce, Brookefield viscometer
Fruit(Orange) Juice:
Measurements of the rheological properties of orange juice can be found in the area of quality control where the flow behavior is a direct measure of its consistency. Moreover, knowing the flow properties of orange juice as a function of concentration, shear rate and temperature allows for improved design of a production plant, since high viscosity products require considerable pumping energy, as opposed to low viscosity or Newtonian fluids. Commercially available clarified orange juice behaves as a Newtonian fluid.
Tomato Sauce:
Tomato sauce or red sauce is a condiment usually made from tomatoes. Like any other processed food, the quality of tomato sauce is determined from the tomatoes (raw material) straight down through all the processing attributes until bottling. Rheological studies help to fix the ideal viscosity which determines its flow behaviour as a pseudoplastic or shear thinning fluid which in-turn reflects on its consistency during different external factors.
Honey:
Honey is a mixture of sugars and other compounds. Measurement of the rheological properties of honey can be determined in the area of quality control where flow behaviour is a direct measure of it consistency. When applied...