TNE1995 New frontier in Hot Filling
Summary : A new filling method using a volumetric pump, without intermediate tank, with speed and capacity control, suitable for tomato-based product. Deaeration of the product, non-formation of foam, total elimination of synaeresis.
Theme(s) : Industrial Technology (equipment, packaging).
Date : November 2000
New frontier in Hot Filling
Despite all the talk about aseptic filling rise, the market statistics show that over 70% of fruit, tomato and vegetable juices in general, are hot filled into various heat-resistant containers. Various tests have shown that it is difficult to distinguish hot filled juices from aseptic filled ones. In the case of tomato, the flavour seems to be better or in keeping the consumer's taste when hot filled.
Contrarily to the aseptic technology, in which the previously pasteurised product is cooled before filling, the present process consists in filling the product at a temperature of about 92-95 °C, and keeping it constant for at least 6 minutes to a temperature of around 35-40 °C to prevent the development of thermophilic bacteria.
A problem with this fillers was that the product, which was held in the tank, might have oxidised and evaporated to the surface, creating a kind of dried film, which might fall into the container, thus altering the organoleptic characteristics of the product. This phenomenon was particularly frequent in the cases of crushed tomatoes, tomato paste and very pulpy juices.
With the new feeding system, which employs a volumetric pump, the tank is eliminated. The pump, equipped with electronic controls for speed and capacity, regulates the quantity of product to be transferred to the filler, adapting automatically to the speed of the filler itself. After the containers have been pre-heated and internally washed with filtered hot water or sterile air, the filling comes about using a machine which applies a light vacuum to the container to evacuate air, whilst the product is introduced by a slight overpressure. This system guarantees a perfect deaeration of the product, the non-formation of foam, constant headspace, the non-formation of steam bubbles inside the container (due to the evaporation "flash" effect), and the total elimination of synaeresis in tomato-based products.
As previously indicated, the filling temperature is of a great importance, therefore, the machine is equipped with two detection systems : one at the product inlet, the other at the recirculation point. If necessary, the machine stops filling and provides to recirculate the product to the pasteurisation, until the correct temperature is reached.
The headspace inside the container is adjustable both automatically by increasing the vacuum during the last filling phase and regulating the introduction height of the valve head into the container.
An automatic CIP device is entirely dedicated to the filling group.
The simple conduction of the system, the high degree in hygiene and flexibility, in addition to the lower cost make this new hot filling system a firm point in the food industry.
(Source : Food and Beverage Processing plants, 39)