Abigail Greenbaum and Kayanush Aryana

Honey is regularly used by bakeries and confectioneries and as an ingredient in many foods and beverages, including breakfast cereals, yogurts, sauces, snack bars, spreads and beer. Researchers in the LSU AgCenter School of Nutrition and Food Sciences are studying the effect of honey on probiotic ice cream.

Honey is a natural syrup produced by bees. The composition and flavor of honey vary with the plant source of the nectar and how it is processed and stored. Honey is composed of approximately 82% sugars, 17% water, 0.2% dietary fiber, and proteins, enzymes, vitamins, minerals and other components.

Honey is 1 to 1.5 times sweeter than sugar on a dry weight basis. White table sugar (sucrose) contains 50% fructose and 50% glucose. Honey contains fructose (approximately 39%) and glucose (approximately 31%). Approximately 9% of honey is composed of disaccharides, including maltose, sucrose, kojibiose, turanose, isomaltose and maltulose. In addition, honey also contains oligosaccharides (approximately 4%). Honey is processed and absorbed more slowly by the body than refined sugar, providing a slightly lower spike in blood sugar, which is easier on the body and digestive system. Honey has a lower glycemic index than table sugar and, therefore, provides a relatively longer and steadier source of energy.

Honey is available in various forms: raw, pasteurized, crystallized, strained, filtered, ultrasonicated, creamed, dried, chunk and comb.

Honey has been reported to have several health benefits, which include treating ulcers and bacterial gastroenteritis and reducing cough and throat irritation. Honey acts as a sleep aid by raising insulin levels, which releases serotonin, a chemical converted to melatonin, a critical component in creating sleep. Honey has antibacterial properties because it has bee-derived antibacterial peptide defensin-1, methylglyoxal, hydrogen peroxide, a high osmotic effect, caffeic acid, ferulic acid and low pH. Several phytochemicals, organic acids, vitamins and enzymes in honey are sources of dietary antioxidants. Honey helps intellectual development through its antioxidants, which help brain cells thrive and stay in great shape. Generally, darker honeys have a higher antioxidant content than lighter honeys. Based on color shades, there are distinct types of honeys, including light, amber and dark. Honey has also been reported to increase the counts of probiotics, namely bifidobacteria and lactobacilli, in the colon.

Lactobacillus acidophilus is a widely used probiotic bacterium with several health benefits. It helps to lower cholesterol and reduce diarrhea in humans. The bacterium also provides immune support for infections and cancer and a healthy replacement of good bacteria in the intestinal tract following antibiotic therapy. It can also improve the symptoms of lactose intolerance, which is important in consuming lactose-containing dairy products.

Probiotic Ice Cream

Ice cream is typically sweetened by sugar. If honey is used as a sweetening source of a probiotic ice cream, it is unclear what effect honey would have on the characteristics of a healthier, probiotic ice cream. The objective was to study the effect of light, amber-colored and dark honeys on the Lactobacillus acidophilus counts and some key attributes of probiotic ice cream.

Vanilla ice creams were manufactured according to published methods with slight modifications. Sugar was replaced with honey, and the probiotic bacterium Lactobacillus acidophilus was incorporated into all pasteurized and cooled ice cream mixes at the rate of 50 grams of frozen culture concentrate per 7.75 liters of ice cream mix. Treatments were light, amber-colored and dark honeys (Figure 1). The control had no honey and was sweetened with sugar. Product manufacturing and analyses were replicated three times.

The L. acidophilus counts of ice creams with honey were significantly higher than the control and a desirable cell density for a probiotic effect upon ingestion. The L. acidophilus counts with amber and dark honeys were significantly higher than the light honey. Unlike sugar, honey has 0.05% to 0.1% amino acids, which may have helped L. acidophilus grow in the ice cream mix prior to freezing.

Pathogen growth is related to pH levels, and a low pH reflects a low amount of pathogen growth. The control had the highest pH. Among the ice creams with honey, use of light honey resulted in significantly higher pH compared to dark honey. Honey usually has a pH between 3.2 to 4.5, while fluid milk used to make ice cream had a pH of 6.8. Because there was no honey in the control to lower its pH, the pH of the control was higher than the treatments.

Ice creams containing honey had significantly less meltdown than the control (sugar). There were no significant differences in meltdown among the light-, amber- or dark-honey ice creams. Use of honey slowed the rate of meltdown, which is desirable as consumers would not want their ice creams to melt rapidly. Unlike sugar, honey contains 0.3% pollen protein, which may have contributed to the increased water-holding capacity and decreased meltdown.

There were no differences between flavor scores of the control and the ice creams containing light and amber honey. The ice cream containing the dark honey had significantly lower flavor scores, perhaps because the dark honey had a stronger flavor compared to the other honeys.

Honey had a desirable effect on probiotic ice cream. Use of honey instead of sugar increased L. acidophilus counts and decreased pH and meltdown volume rate. Light- and amber-honey ice cream had flavor scores comparable to the control vanilla ice cream. Light and amber honeys can be recommended for manufacturing L. acidophilus probiotic ice creams.

Abigail Greenbaum is a former Undergraduate Research Grant student, and Kayanush J. Aryana is a professor in the School of Nutrition and Food Sciences.

This article appears in the spring 2019 issue of Louisiana Agriculture.

The study of probiotic ice cream was conducted by Abigail Greenbaum, the recipient of a College of Agriculture Undergraduate Research Grant. Her supervisor was Kayanush J. Aryana, in photo, who is a professor in the School of Nutrition and Food Sciences. Photo by Olivia McClure