Long-term freshness is typically thought of as a formulation challenge. But today’s clean label and free-from movements have food manufacturers looking elsewhere to extend or preserve the shelf life of baked foods.
While change is slow to come in bread bagging, other types of packaging for baked products are evolving with resealable features, thicker films and materials, and modified atmosphere packaging. Consumers are looking to buy foods that not only fit their lifestyles but also won’t spoil after a few days.
First, food manufacturers should think about the sanitary design of bagging and closing machines. Nick Taraborelli, vice-president of sales, Paxiom Group, said bakers need to know how easy a machine is to operate and how simple it is to clean before purchase. Cleanability protects products from contaminants that can negatively affect their appearance, safety and freshness, he said.
Dennis Gunnell, vice-president, sales and marketing, Formost Fuji, agreed that sanitation is a vital first step when addressing long-term freshness goals.
“That’s something the industry really needs to embrace — sanitation — and looking at the equipment to make it more sanitary will go a long way to help freshness and a cleaner product,” he said.
Once a product is in a bag, there are several additional ways to achieve extended shelf life. Modified atmosphere packaging such as nitrogen gas flushing is popular for food service items and perishable retail goods. Oxygen scavenging compounds, too, are widely used to protect the integrity of baked foods and snacks.
“At the actual bakery, producers only have two steps of control for freshness,” Mr. Taraborelli said. “One is the package material itself and second is whether they choose to inject a foreign gas like nitrogen into the package to give it more shelf life.”
The decisions a food manufacturer makes on the packaging line, from bag material to the closure, affect how the product performs in the days, weeks or even months to come.
It’s in the bag
Choosing a proper bag and closure mechanism for bread, granola bites, chips or any other baked snack is critical. Each product has a variety of challenges when thinking of ways to better protect from lipid oxidation, microbial growth and moisture loss.
Mr. Taraborelli said the Paxiom Group has seen a proliferation of requests for stand-up zipper pouches over the past five years.
“There’s been a very noticeable switch from carton packaging, as well as vertical form/fill/seal pouches like a pillow pouch and a move to high-quality, reclosable pouches that are much easier for the consumer to save for further use,” he said.
Stand-up zipper pouches are used more for baked snacks, crackers and cookies because they offer resealability and convenience and they present well on store shelves, Mr. Taraborelli added. Paxiom’s stand-up bag machine, the Swifty Bagger, was engineered with a straight-line, ergonomic, easy-to-service and quick-to-clean design. It operates on a variety of bag styles, including three- or four-sided seal pillow pouches, stand-up bags, gusseted pouches and quad-seal bags. The benefit of resealable stand-up bags, Mr. Taraborelli said, is that they can be closed to protect from further oxygenation or staling of a product.
Sealing these stand-up style bags can be more complicated because of thicker, more protective materials. TNA’s robag 5, introduced in March at SNAXPO18, was designed to deliver high-quality seals at greater speeds on a wide range of films and bags.
“One of the main priorities during the bagging process is a high quality of seal integrity as this directly affects the shelf life of the product, in particular, during modified atmosphere packaging where the bag needs to be 100% air tight,” said Alf Taylor, chief executive officer of TNA.
To do this, TNA bagging systems come with security measures like product in-seal detection. This technology automatically triggers a reject mechanism if it detects a product or particles in the seal area of its bags. To further ensure seal integrity, TNA can install cross feeders with integrated sifters to remove small particles from the line before product reaches the bag. Baked goods often produce debris that affect a seal and, thus, the freshness of a product shipped to consumers.
For bread, the traditional pre-made bag still reigns king for consumers. Although alternatives like overwraps that extend bread freshness are available, they have been slow to impact the U.S. market. When thinking about materials for vertical pouches or bread bags, it’s important to think about consumer-friendly design, marketability and oxygen barrier qualities.
The material matters
Packaging equipment suppliers encourage bakers to work closely with material manufacturers to ensure the bag not only protects the product but also conveys the quality desired. A film’s structure, thickness and oxygen barrier properties are key.
By combining different laminates, Mr. Taylor said, it’s possible to achieve specific film functionalities depending on what’s required in terms of barrier properties, sealability, printability and overall appearance and feel of the bag.
“Metallization, for example, can improve the film’s barriers to moisture, air and odors and adds a glossy shine to the packaging, improving the overall aesthetics of the bags,” he said. “However, additional coatings increase the overall thickness of the film, which in turn affects the sealing temperature, pressure and time required to achieve the necessary seal integrity.”
TNA’s robag 5 can maintain high-speed seal integrity by integrating ultrasonic back-seal technology, which helps overcome the thermal transfer limitations of traditional heat seal methods. In addition, TNA’s high-thermal conductivity jaws are made from a composite material and can deliver quality seals even on thick laminate films.
“Together with our product in seal detection technology, these innovations can help manufacturers limit waste and produce quality snacks with a long shelf life and high consumer appeal,” Mr. Taylor said.
Two common materials used in bread bagging are polypropylene and polyethylene films. Both come in a variety of thicknesses ranging from 1.25 mm to 2 mm, and each have their own strengths and weaknesses. Low-density polyethylene is widely used in the United States and is the least expensive, but it has limited oxygen barrier qualities.
“Polypropylene has been proven to be the best material for bread bags and for maintaining freshness,” said Wouter Reijndorp, managing director of sales, Europe, Middle East and North America, for Kwik Lok. “It allows the bag to be stored in the freezer and offers clarity in the overall bag presentation.”
The thickness of a bag can directly impact the process on the packaging line. The process might also need to slow down to accommodate increased changeovers or increased heat seal time.
“If bakers go with a thicker bag, then we might tweak the machine a little bit or talk to them about using fewer bags on a wicket,” said Justin Atkins, director of sales, Bettendorf Stanford. “If you go to a bag that’s twice as thick, the same number of bags is going to be twice as heavy and twice as tall. So, you have to tweak your machine to handle that extra weight in terms of keeping the bags level and in place for the perfect inflation and transfer of product.”
Bettendorf Stanford’s scoop baggers can handle up to 65 loaves per minute for pan bread and up to 50 per minute for artisan types. Typically, artisan bread requires thicker material to protect the bag from tearing and give the bread a higher quality packaged look.
Thicker bags have an impact on a system’s ability to scoop, open and push a product into it. AMF Bakery Systems’ baggers do all of this in less than a second per loaf. The material must be just right to ensure product integrity and efficiency.
“The material is very critical to the process,” said Bobby Martin, executive product manager, AMF. “A plastic film that is too thin will break apart. Thicker material is better specifically with hard-crust breads.”
Sealing the varying thicknesses is also a tight-rope act. Low-density polyethylene has a very narrow window to heat-seal it, Mr. Taraborelli said. And the material melts very easily, meaning a machine needs time to cool it down before moving on to the next seal.
“It may be the least expensive package one could purchase in terms of material cost, but it’s the hardest to seal and takes the longest, yielding the least amount of cycles per minute,” he said.
The thicker the material and the faster a line is moving means a sealer must maintain higher heat. Mitch Lindsey, technical sales, Burford Corp., said the company’s tamper-evident sealer retains higher heats to keep production moving with its upper and lower manifolds and ambient air intake system.
“Those three things help maintain whatever your setting may be,” he said. “If you’re running 70 bags a minute on a 1.25 mm bag, you may run 400°F, where that same speed in a 1.5 mm bag might take 450°F.”
Ensuring a proper seal on a bag ensures freshness through the purchase of a product. But once that seal is broken by a consumer, all steps taken to protect a product from oxygen go out the window. That’s where reclosability comes in.
Tying up the loose ends
Bakers have many options when looking at closures for their products from heat-sealed bags to twist tyers to tape closures. Each one offers different benefits. Some can get a tighter seal on a product with tamper evidence appeal, while others offer a basic closure that lends itself to resealability and reuse.
Mr. Lindsey said the Burford twist tie offers a tight closure that can be reused on both polypropylene and polyethylene bags. The gauge of the wire in the tie can vary depending on the product and bag material. The company’s tape closure system provides tamper evidence and resealability. The tape’s paper backing is torn to open the bag, but consumers can reuse the adhesive to close the bag again.
Kwik Lok’s clip closures are designed to grip a bag at six separate points, locking the clip in place and ensuring a tight and secure package. No matter the closure device, size must be measured properly.
“If the closure is sized correctly for the bag, long-term freshness for the life of the bakery product are the same for all closures if sized and applied correctly,” Mr. Reijndorp said.
The only thing left to do is decide which closure can extend shelf life, while protecting and promoting a product.