Sepallo Food Ingredients, Barrhead, Alberta, Canada, manufactures fruit and vegetable powders, which it markets primarily as bulk ingredients to manufacturers in the food and natural products industries. Recently, the company was faced with finding a way to improve its freezing process. Too much of its high-quality first-cut product was ready for harvest early in the season for its dryer to handle. Additionally, once the harvest season was over, the plant needed to look for other sources of materials to keep its dryers busy in the winter months.
To maximize its own organically grown harvest of high-value and high-quality wheat, oat, pea and spinach plants, the company had been hermetically sealing the excess juice from the primary process (the evaporator) in 40-lb plastic bags and batch freezing the product in its storage freezers. The plant then would bring out the frozen bags later in the year and further process the product in dryers.
For the juice product to freeze properly in the bags, the level of concentrated solids in the juice had to be held to about 16 percent. Higher levels would prevent the product from freezing solid in the core of the bag.
Also, when additional batches of fresh juice product were loaded into the freezer, the additions negatively affected the freezer’s operation. As each new batch was introduced, temperature fluctuations would occur, and a greater amount of time would be needed to freeze the product solid.
Another consideration was the retention of nutrients in the juice.
“We wanted to reduce any negative influences on the juice quality. Because of the load we were putting on the freezers each day by adding large amounts of unfrozen juice, it often took up to 18 hours for us to have a complete freeze on the juice bags,” explains Brad McNish, Sepallo president.
Juice begins to degrade as soon as it is pressed, so time is of the essence when working with juice products. The degradation will accelerate until the juice is stabilized either through drying or freezing.
“Because we are dealing with chlorophyll, the first sign of oxidation is browning. We were seeing byproducts of oxidation in our juice bags,” says McNish. “While this occurrence was not normally detectable by the naked eye, a color meter allowed us to measure the change.”
Plant personnel also found that the frozen 40-lb juice bags were more concentrated in the center than at the periphery - that is, the ratio of juice to water increased from the periphery to the center of the bag. This situation is commonly seen in a typical ice cube, where the outer part of the cube is clear (pure water) and the center is cloudy white (solids). This effect is a result of the pure water freezing first on the outer, colder surfaces; the solids concentrate at the center, which is the last place to freeze.
In addition to the plant’s juice quality and concentration issues, the entire process was labor-intensive. Manual tasks at the plant included filling and sealing the bags, loading and unloading the freezer, cutting the bags open, disposing of the bags, crushing the blocks of ice and then feeding the dryer.
A Better FreezeTo resolve these issues, McNish contacted Berg Chilling Systems Inc., Toronto Ontario, Canada. The company installed a modified version of its shell icemaker to process the excess juice, freeze it in bulk, and deliver the frozen juice directly into reusable and stackable 0.5-ton storage totes with securely latching lids in the freezer.
The 10-ton-per-day industrial icemaker is cleaned easily on a daily basis to meet the stringent sanitary conditions of the food processing industry. The frozen juice is conveyed automatically from the end of the ice machine’s discharge auger to a connecting auger that delivers the juice ice straight into the freezer. Once inside the freezer, the ice falls into the reusable and closable totes until the tote is full. It then is sealed, labeled for batch identification, stacked and stored in the freezer for further processing later in the season. The plant operators have discovered that they can freeze a more concentrated juice on the shell ice machine, so they are evaporating more water from the juice before sending it to the icemaker.
“We now are successfully freezing juice at 21 to 22 percent solids, which is 5 percent higher than the bag system and improves our throughput,” says McNish. (Ten tons per day at 22 percent solids, compared to the previous level of 10 tons per day at 16 percent solids, is an additional 0.5-ton per day of solids, which translates into more powder.)
Because the juice product now enters the freezer already frozen, the plant is no longer experiencing temperature fluctuations with the introduction of new product. Additionally, the product already in the freezer is now held at a constant temperature, eliminating the potential for oxidation. The result was an instant freeze of the juice, preserving its quality for processing later and significantly reducing labor.
“Now that we are using the Berg freezing system, we are freezing our juice instantly, and the frozen juice when measured is showing zero signs of browning through oxidation. This directly impacts our bottom line,’ says McNish. “Additionally, it is a requirement from some of our customers that we meet a minimum chlorophyll level. Our thawed juice from the Berg freeze system is the brilliant green of fresh juice.”
Overall, Sepallo has found that the shell- ice-shaped juice nuggets have resulted in easier handling, and the greater surface area of the juice nuggets allows for faster thawing, which requires less energy and time. The company has purchased a bin dumper for its forklift, which will remove the manual component associated with handling the 40-lb blocks as before.
“The bottom line,” says McNish, “is that we have improved our frozen juice quality dramatically. We have eliminated wasteful and costly handling steps. We have increased production as we now are freezing more juice at a higher solids level per 24-hour period. And less manpower is required, freeing up staff for other tasks.”
According to McNish, the return on investment can be rationalized in several ways:
- Cost savings though reduced freezer operating costs and
- Improvements in product quality and production yields.
- Improvements in freezer storage efficiencies, which allow more frozen solids to enter the freezer per day and provide the company with more product to sell at the end of the year.
Berg Chilling Systems Inc. manufactures industrial thermal process control systems for a range of industries. For more information, call (416) 755-2221; e-mail firstname.lastname@example.org; or visit www.berg-group.com. For more information about Sepallo Food Ingredients, visit www.sepallo.com.