Tag Archives: Water Activity

Enjoy the Perfect Pasta

casestudy

JOWA AG Pasta has been the largest manufacturer of pasta products in Switzerland since it was founded in 1931. It is important for the company that its production operations run smoothly and meet strict quality standards.

Original Article from www.rotronic.com

Precision temperature and humidity probes from Rotronic are used to measure the climates in the factory’s six production lines, which predominantly manufacture dried pasta for the retailers such as Migros (Switzerland’s largest retailer). As a testament to the quality of Rotronic probes some units are over 15 years old and are still performing as required having only undergone routine calibration and adjustment to ensure that they provide consistently accurate accurate data.

JOWA AG manufactures 18,000 tonnes of pasta per year and is thus the largest pasta producer in Switzerland!

The pasta market is highly competitive and food legislation strict. It is therefore all the more important that the pasta is produced in the finest quality without production stoppages and rejects. The drying process plays a key role in the production of dried pasta and is therefore accorded top priority at JOWA. In order to control the climates optimally, temperature and humidity probes from Rotronic are used in the production lines. To preserve the food for a long shelf life and prevent mould and negative microbiological processes, the pasta is dried to a very specific level. Over drying wastes time, energy and produces a poorer quality product, under drying reduces shelf life and risks spoilage. Humidity and temperatures therefore need to be monitored closely during production. Legislation in Switzerland states that pasta products may not contain more than 13 percent water.

High Demands on Probe Accuracy

JOWA has been manufacturing pasta at its site in Buchs AG since 1963. The requirements of food standards, law and customers are rising continuously.

pasta
Spaghetti Production!

Oliver Höfler, head of the JOWA AG sites Pasta Buchs & Mühle Wildegg, comments:

Every single production step needs to be traceable in ever more detail, down to each single packet of spaghetti. The temperature and humidity of each production step must be recorded exactly.”

 

If unwanted temperature and humidity variations were to occur in the pasta, this could lead to quality defects such as crumbling. The pasta would then dry irregularly and break during cooking. For this reason a sample is taken of every product from the first three and last three pallets for quality assessment. The heads of the different departments evaluate the products daily according to various specified properties such as taste and appearance.

Oliver Höfler explains: “If we have to recall products from various stores, this means an enormous financial loss of several ten thousand francs and also a severe blow to the image of our products. A dissatisfied customer – that is something we cannot afford. For this reason it is essential that we are able to rely on the measuring accuracy of the Rotronic probes to 100 percent.”

In addition to this, samples need to be taken for analysis from ongoing production every four hours. “ We greatly appreciated the open and transparent collaboration with Rotronic.” Oliver Höfler, JOWA AG, Switzerland Migros dried pasta perfectly monitored. Rotronic I200 sensor, providing reliable service for more than 15 years.

Project Workflow: Good and Long-Term Planning

Planning calibration time is the key to success with humidity instruments. JOWA AG in Buchs stops production twice a year, two weeks in winter and two weeks in summer, in order to check all equipment and machinery and so maintain the high quality standards. Andreas Zülle, head of production, ensured that the 50 probes (both the I200 transmitters dating back to at least the year 2000 and the newer HygroFlex5 generation) were disconnected right at the start of the last inspection so that Marko Schulze, Rotronic’s qualification technician on site, could begin calibrating the measuring devices. All probes were also catalogued. Marko Schulze: “JOWA’s planning was ideal, I was able to check all probes and either get them back into shape or replace them, and then we still had enough time to test the newly adjusted probes.”

Product Focus – Rotronic HygroFlex5

hf_stahl_wand_front67_1

The HygroFlex5 series of transmitters connect to our entire range of HygroClip probes and offers analogue and digital outputs for any application.

HC2-S probe provides superb precision and state-of-the-art functionality, taking humidity and temperature measurement to a whole new level of accuracy < 0.8 %rh and < 0.1 K at 23 °C.

Also available with ATEX / Intrinsically safe certification.

 

Smooth implementation of the inspection and calibration procedure was important to Andreas Zülle: “After the calibration, our process specialists were able to start up the production lines again without problem.” Oliver Höfler adds: “We greatly appreciated the open and transparent collaboration with Rotronic, found Marko Schulze to be an extremely competent partner and are sure we will be able to carry out calibration of our instruments even more efficiently next time. They have now been catalogued in detail. On top of that, we can also check the probes during operation with the Hygropalm from Rotronic.” Both sides benefit from good planning and a good working relationship.

Some Interesting Facts about Jowa

  • JOWA Pasta has been producing dried pasta for more than 50 years
  • The durum wheat semolina needed for production comes from a mill in Wildegg that also belongs to JOWA.
  • A team of 46, working three shifts a day, ensure daily that high-quality raw materials are transformed into products at an optimum price-performance ratio .JOWA.jpg
  • JOWA employs a workforce of around 3,200 people and, with more than 140 apprentices and trainees, is the biggest training company in the Swiss bakery industry.
  • JOWA AG is the leading Swiss bakery and supplies its customers from the retail trade, convenience stores and food service sector daily with a wide range of products and individual service concepts.
  • Jowa produce buns, cream slices to pasta, ham croissants and braided bread, some even gluten-free – the bakery assortment goes far beyond the classical bakery range.
  • The service concepts are tailored specifically to the requirements of customers and extend from logistics and marketing to in-store production.
  • The tasty JOWA breads and pastries are very popular.
  • JOWA breads are served fresh on the table daily in every third Swiss household.

 

Sugar Production and Relative Humidity

The sugar market worldwide

Sugar is one of the most important raw materials traded on the worldwide markets.

Top 5 sugar producing companies

1. Suedzucker AG,

2. Cosan SA Industria & Comercio

3. British Sugar PLC

4. Tereos Internacional SA

5. Mitr Phol Sugar Corp.

In the 18th century only a few countries were producing sugar. However, these days over 100 nations process different base materials into sucrose. Remarkably India, China, Brazil & the European Union alone deliver 50% of the global demand.

Sugar Facts:

– Worldwide 170 million tons of raw sugar were produced in 2011/2012

– Brazil, India, China & EU are the most important sugar producing nations

– With an annual consumption of more than 24 million tons India, is the world’s largest market for raw sugar

Raw materials & processing

In temperate regions such as West, Central & Eastern Europe, the United States, China and Japan raw sugar is produced from sugar beet. However in the tropics and subtropics sugar is extracted from sugar cane.

800px-cut_sugarcane

Sugar cane & Sugar Beet

Processing

The processing of these two raw materials only differs in the first few steps. The main goal is to extract the juice, containing the sugar,  as efficiently as possible.

Extracting the sugar

Sugar cane is cut into small pieces during the harvest. It is then put through an industrial press to squeeze out the sweet sap.
Sugar beet has to be processed in extraction towers, where the plants release their sugar during a hot water treatment at 70°C.

Evaporation

After filtering the juice the water is extracted by passing through different stages of evaporators until only a thick syrup is left consisting of around 70% sugar.

Crystallisation

The syrup is then boiled until sugar crystals are formed. These crystals are then cleaned through centrifugation. To further improve purity this process is repeated twice.

Cooling & drying

Now the sugar has to be dried. One option is in large scale drum dryers at a temperature of 60°C. after drying, the sugar is cooled down on fluidized-bed coolers before heading to the warehouse or packed for shipping.

Trommel2_400_219_01

Inside a drum dryer.

Storage & logistics

Sugar belongs to the group of hygroscopic goods with an extremely low water content – below 1.5%. Basically sugar is a robust material but vulnerable to high humidity and temperature changes.
Generally it is recommended to store and transport sugar at a temperature of 20-25°C and 25-60% relative humidity.

By taking a closer look at the adsorption curve of sugar it is easy to see that over a long range of relative humidity the product quality is not affected. But as soon as the humidity level rises to 75% sugar starts to clump and above 80% relative humidity even dissolves .

Storage

Immediately after production the refined sugar is stored in humidity controlled sugar terminals or ventilated silos connected to dehumidifiers.

6.2.4. Sugar Terminal 5086

Sugar in a storage terminal

Logistics

Large quantities are trans-ported in silo trucks or train wagons. When sent by ship sugar is packed in double-walled bags made of natural fibre and plastic. If sealed like this, temperature is the crucial parameter which can affect the quality of the sugar. Due to big differences in temperature water vapour left inside the bags may cause clumping and even liquefaction.
The finer the sugar, the higher the risk of clumping.

Caking-dark-brown-sugar

Sugar clumping

Why the need to measure humidity?

As seen above, temperature and humidity measurements are crucial parameters in the sugar industry. Due to its hygroscopic behavior sugar can resist small changes in humidity, and slight temperature variations are not a major problem. But as soon as relative humidity rises above 80% or temperature changes significantly, the product can be destroyed as it clumps or even turns liquid.
During the process of evaporation, crystallisation, drying and cooling temperature and humidity play a huge role.

Philip Robinson                                                                                                        Rotronic UK

 

Water Activity and Moisture Content… What is the difference?

Water Activity and Moisture Content are two very different parameters which are often confused and misused.

In a meeting today with a manufacturer of coffee capsules and pods, these differences were critical.

– Their  whole bean supplier provided each batch with  moisture content readings.

– However customers buying the coffee capsules and pods were asking for detailed water activity measurements for each batch. In addition for BRC Food Safety and shelf life validation of the final product, water activity was required.

Why are there these differences and can one measurement be used to determine both values?

Moisture content is probably the simplest value to understand.  It is simply the quantity of water contained in a material. Traditionally measured through loss of weight on drying. This method raises some issues, depending on the drying temperature you may not remove all water or may also remove other non water compounds.

More modern methods resolve these issues and use infra red absorption. This way the water content is directly measured, the method is non-destructive and far quicker. 

Moisture content is typically given as a percentage in terms of weight.

Infrared Moisture Measurement
Infrared Moisture Measurement – A measure of moisture content through IR adsorption

 

Water Activity (aW) is a measure of the free water in a sample, and ranges between 0…1.  Pure water would have an aW of 1.0. As water activity measures the ‘free’ or ‘active’ water in a sample it is more relevant to growth of organisms, chemical processes, enzyme activity and physical parameters like size and clumping as these are only effected by the water that can be chemically interacted with. Interestingly Water Activity is related to Moisture Content but it is product and temperature specific.

aW… is more relevant to growth of organisms, chemical processes, enzyme activity and physical parameters

Rotronic HygroLab
Rotronic HygroLab Water Activity Measurement – A measure of the ‘free’ water

What is free water? Water can be bound in materials in two broad ways.

1. Chemically Bound Water. Is bound so tightly that it cannot be utilised by bacteria, enzymes etc. It can be removed  through high temperature heating.

2. Free Water. Is bound through weak bonds, structural diffusion, capillary condensation and surface binding. It can be utilised by bacteria and can exchange with the environment, it is also removed through heating.

For instance a whole grape would have the same moisture content as two halves of the same grape. However the aW would be far lower in a whole grape as much of the water is bound inside the grape skin and only made free when the grape is cut in half!

Take a look at our Water Activity white paper or our Knowledge base for more information.

Introduction to Water Activity

Water Activity White Paper and Product Overview

Application note F004 – Water activity in the food industry