Pasta’s Invariable Variables

Dried pasta has earned a strong position in today’s marketplace due to the ever-increasing demand for convenient food with an authentic and international edge. In 2006, the market for pasta in Asia-Pacifi c was worth an estimated $1.08 billion, and global value sales grew by over fi ve percent. At this time, there are no signs of this demand diminishing. Dried pasta is one of the most versatile and readily-available foods. The delightfully easy preparation of pasta may lead people to believe that its production is equally simple and straightforward. In reality, dried pasta undergoes a precise manufacturing process and must pass a catalogue of quality-control tests before it arrives on supermarket shelves. This is essential not only for consumer acceptance and enjoyment, but also to stay ahead of other producers in a fi ercely competitive market. Pasta manufacturers must constantly strive to improve their production methods and explore every possible quality assurance measure, in order to profi t in this sector. Thus, objective analysis is crucial. While traditional taste panels are still a valuable method for monitoring the quality of cooked foods but, in the case of pasta, sample sizes can often be limited or, in contrast, too great in volume. This is also a very time-consuming process. Ideally, taste panels should be complemented by instrumental tests for assessing factors such as elasticity, fi rmness, stickiness and cooking tolerance.

Flour variations
Pasta is manufactured in a huge array of shapes and sizes, using a variety of ingredients. Under Italian law, dried pasta must only be made from durum wheat semolina fl our. However, numerous attempts to speed up the manufacturing and cooking processes in other countries mean that it is often produced using other types of fl our. Some pasta fl ours give a softer end-product than others, or may lead to shorter cooking times. Furthermore, the quality of ingredients used and processing methods employed are another source of product variables.

Such nuances in production, preparation and consumption can make quality-control testing in pasta complex and subjective, particularly when product quality must be judged according to its uncooked, as well as its cooked, state.

It is important to analyze the texture of dried pasta during every stage of its production and consumption, considering every possible variable. Only then will manufacturers be able to identify potential shortcomings and eliminate them, in order to ensure that their consumers always enjoy a high quality end-product. In a market where brand loyalty is low, disappointment must be avoided.

Drying hazards
Once dried, most pasta still contains approximately 12.5 percent moisture. It can have a shelf-life of up to three years—one of the reasons it remains a store cupboard staple throughout the world. Retaining this exact amount of moisture is paramount—the difference between pasta relative humidity and environmental relative humidity (ERH) can often be the root cause of a product’s fl aws. Because both manufacturing and packaging infl uence relative humidity, both must be carefully controlled.

The process of drying pasta is the most complicated and critical step in its production. The most unwelcome outcome of the drying process is “checking”, where moisture gradients are created as a result of the pasta being dried too fast, leading it to crack. This may happen immediately or, worse still, weeks after the product has been packaged, resulting in negative consumer response and consequent sales losses.

The breaking strength of dried pasta can be a good indication of how well it has been processed. It can also indicate a product’s gluten quality, which determines the pasta’s tolerance of shipping, and how well it will cope with the cooking process. All these potential variables in the manufacturing process should be considered by manufacturers before the product is packaged or, more importantly, cooked.

Cooked or overlooked?
During and after the cooking of dried pasta, a further category of variables arises that may threaten the textural appeal of the product. Of course personal preference plays a large role at this stage. Consumers’ actions will have a signifi cant bearing on cooked quality, which is infl uenced by type of water and quantity (relative to pasta), use of salt, cooking time and temperature and the act of draining.

Objective analysis is crucial. Traditional taste panels are still a valuable method for monitoring the quality of cooked foods but, in the case of pasta, sample sizes can often be limited or, in contrast, too great in volume. This is also a very time-consuming process. Ideally, taste panels should be complemented by instrumental tests for assessing factors such as elasticity, fi rmness, stickiness and cooking tolerance.

In 1989, the AACC approved a standard method for measuring pasta fi rmness, which is now widely used by manufacturers all over the world. This specifi es the use of a knife blade and assessment of the force required to cut through pasta strands. Despite being much more objective, this testing method is not suitable for smaller pasta shapes.

Pasta stickiness has proved even more diffi cult to quantify. Although relative humidity has a large part to play in the surface texture of the pasta, it can also be affected by unabsorbed water, drainage methods, water type and wheat class. Developing a test that can take all these variables into account is challenging. As a result, analysis methods for pasta stickiness, along with other potentially complicated tests for cooked and uncooked dried pasta, has been relatively unexplored—until now.

Putting penne to paper
Stable Micro Systems has developed a number of pasta-testing attachments for its TA.XTPlus texture analyzer. These rigs consider all recognized variables in the dried-pasta manufacturing and cooking process and seek to objectively analyze them.

The breaking strength of dried pasta can give an accurate indication of its brittleness or fl exibility, which refl ects the effect of the ingredients used to make it and possible moisture uptake. Stable Micro Systems’ three-point bend test applies pressure to the center of a dry spaghetti, noodle or sheet-pasta sample, analyzing the force applied before the sample reaches breaking point. This gives an accurate indication of pasta strength, allowing manufacturers to examine fi nished-product anomalies and consequently eradicate them.

The Spaghetti Flexure Rig has been developed by Stable Micro Systems to monitor potential cases of “checking”. In this instance, uncooked spaghetti is cut to a known length and positioned between upper and lower supports on the TA.XTPlus texture analyzer, in centrally-located holes. Force is then applied, causing the sample to fl ex to its breaking point. A low force indicates a weak product, while a high force signifi es product strength.

In cooked pasta, fi rmness, stickiness and tensile strength give a good suggestion as to the quality of the product. While the AACC-approved Knife Blade rig is still suitable for longer goods, Stable Micro Systems has developed a method for its Kramer Shear Cell attachment to deal with smaller, non-uniform pasta shapes. In this test, a number of pieces are tested in bulk. Their fi rmness is determined by an average of the forces used to cut through the sample.

Stable Micro Systems’ Pasta Firmness/Stickiness Rig uses a rectangular aluminum probe to assess the adhesive properties of pasta. The probe applies a compression force onto the sample from above and then withdraws at a maximum speed.

The latest test method developed by the company uses a Spaghetti/ Noodle Tensile Rig to perform tension tests on loops of pasta or noodle sheet (the preparation of which is provided by a carefully designed annular cutter). These assess elasticity and breaking strength, giving an indication as to how the product will perform during cooking or during transport, as part of a ready-meal, for instance.

Controlled testing using Exponent software such as this not only provides clear quality-assessment standards but can also indicate how pasta products will react to further processing during manufacture. For manufacturers, the aid of repeatable, scientifi c analysis will help in gauging product quality and achieving maximum repeat purchases.