Whey is a liquid by-product in cheese making and is usually dumped because it has no value. It is the greenish translucent liquid which remains after the curds are formed and drained in cheese production.

Research studies, however, indicated that whey has important nutrients like lactose, protein, minerals and vitamins. Its protein is considered as high-quality in terms of nutrition, flavor, functionality and value necessary to create great-tasting sports product formulations.

Previous literature has also proven that whey has the  “highest biological value and protein efficiency ratio and contains all of the essential amino acids required by the body for good health.” It can also deliver the benefits of “burning more fat while retaining muscle,” “increasing lean muscle” and “enhancing physical performance” over other protein sources consumed after exercise.

Thus, whey, can also be processed into beneficial products like sports drink and whey vinegar, among others.

Sports drink

The study titled, “Development of Lactase - Treated Isotonic Drink from Whey”, explored the possibility of using whey to develop a sports drink (isotonic beverage) from lactase-treated whey.  It was conducted by Central Luzon State University (CLSU) Bachelor of Science in Food Technology students  Lynnden Castillo, Charlene Mae Lazo and Rafael Amurao under the supervision of Dr. Alma De Leon of the College of Home Science and Industry  and Mina P. Abella of the Philippine Carabao Center (PCC). 

Specifically, the researchers aimed to determine the efficiency of lactase enzyme in reducing the lactose content of the whey, the physico-chemical properties, sensory characteristics and nutritional composition of the isotonic whey drink, as well as the percent yield and production cost of the by-product when made into a sports drink.

Lactase is an enzyme that degrades or reduces the lactose (milk sugar) in whey. It is used to increase the solubility and digestibility of the sports drink, thus, making it more ideal for consumers who are lactose intolerant.

In the development of isotonic drink from lactase-treated whey, the following were considered: hydrolysis of whey; optimization of parameters such as temperature, reaction time and concentration; lactase determination of glucose in hydrolyzed whey; preparation of isotonic drink from hydrolyzed whey; and product evaluation. 

In the process of hydrolysis, acid whey was treated with lactase to hydrolyze the lactose in the whey.  Hydrolysis of lactose was conducted by adding lactase to the whey at a rate of 2% and at 23oC for 1 hour. Results of the study showed, at the optimum condition, lactase has the capability to reduce the lactose content by 92%.

Hydrolyzed whey, together with other ingredients was well blended and the pH of the mixture was adjusted to 3.8 to 4.3 using 10% citric acid.  Thereafter, the drink was heat-treated to a temperature of 92oC for 2 minutes and hot-filled into PET bottles and sealed.   Two treatments were used in the study: one with mango, lemon and orange flavors and another one with no flavor is the control treatment.

Meanwhile, the physico-chemical characteristics, microbiological quality and nutritional information of the isotonic drink were also determined in the study.  In the sensory evaluation, the researchers used key performance indicators (KPI) such as overall acceptability, product ratings such as liking, and just-about-right on specific attributes such as color, aroma, taste and mouthfeel.

Based on the overall results, the following highlight the findings:

No viscosity was observed on all treatments, though the highest total soluble solid (TSS) was found in the orange-flavored isotonic drink, which is not significantly different from the lemon-flavored drink. 

Nutritional analysis also revealed that mango flavored whey drink has total calories of 73.34 with a carbohydrate content at 7.20%, which qualify it as an isotonic drink (a drink is said to be isotonic if its carbohydrate content is within 4%-8%). Furthermore, the isotonic whey drink has low fat content at 1.93% and a protein content at 6.79%, which makes it a good source of amino acids.

Other than that, the mango flavor was the most liked sample, followed by lemon and orange flavors.  Likewise, the flavor with the highest purchase intention by customers was found to be the mango -flavored isotonic drink. 

And based on all sensory evaluation attributes conducted in the study, majority of the panelists rated all treatments as “just-about-right” in terms of its color, aroma, taste and mouthfeel.

Meanwhile, during the storage at ambient temperature, the total aerobic plate count and yeasts and molds count of isotonic whey drink are found to be within the FDA standards up until the 4th week of storage. The salmonella, coliform and E.coli counts in the isotonic whey drink are all found negative, which meets the FDA microbiological standards for ready -to-drink beverages.

All treatments, based on the penalty analysis, can still be improved by increasing the levels of fruity flavor, sweetness, mouthfeel, sourness, overall flavor and aroma, according to the study.

The cost of production per 250ml isotonic drink was at Php 26.09.

The range of purchase decision from the 50 panelists, meanwhile, was found to be at 3.62 to 4.06. It meant that consumers will “probably” and “definitely” buy the developed isotonic drink when it becomes available in the commercial market.