Date of Award

Summer 8-17-2018

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Food Science and Human Nutrition

Advisor

Mary Ellen Camire

Second Committee Member

Denise Skonberg

Third Committee Member

Anne Langston Bowden

Abstract

Seaweed is becoming popular across the world as consumers learn about the variety of seaweed-based products and their health benefits. Sugar kelp is one of Maine’s seaweed varieties that is locally grown each year. Sugar kelp and similar species contain many useful nutrients including iodine, calcium, magnesium, iron, and vitamins A, B, C, and E. Even though the health benefits of seaweed have been proven, locally-sourced seaweed has not yet become any more popular in Maine. Part one of this study identified suitable processing steps for a sugar kelp-based broth. Part two assessed how consumers’ demographics and food neophobia, as well as products’ characteristics, impacted broth acceptability.

Broths were produced from fresh and frozen kelp, and several methods for flavor extraction were evaluated. An incomplete factorial design was selected for chemical and physical analyses. Fresh and frozen kelp were treated by boiling for 15 minutes or steamed for 30 minutes. The resulting broths were strained to produce clear broths. Sugar kelp was harvested on three dates in 2018 (April 20th, May 29th, and June 7th) to help understand how harvesting dates may impact broth attributes. A commercial reduced-sodium vegetable broth served as a control sample and had had the highest sodium, glutamic acid content, total solids, and viscosity. The control vegetable broth had the lowest pH and L* value for color. The broth made using fresh sugar kelp had the highest L* value. For all other chemical and physical assays, no significant differences were found between the sugar kelp broths.

Fifty-six consumers evaluated three sugar kelp broths (frozen kelp boiled for 15 minutes, frozen kelp steamed for 30 minutes, and fresh kelp steamed for 30 minutes) and the vegetable broth control. The vegetable broth control scored significantly higher than all the experimental sugar kelp broths (p ≤ 0.05) for aroma, flavor, and overall acceptability on a nine-point hedonic scale. The vegetable broth scores were approximately 7.0 (like moderately), while the experimental sugar kelp broths scored between 4 (dislike slightly), and 5 (neither like nor dislike) on the hedonic scale. All broths were liked similarly for appearance and thickness. Almost 60% of panelists were female, and all but one person had previously eaten seaweed. The most frequently-sought food label information were ingredients, nutrition facts, and geographic source of the food. The Food Neophobia Scale scores for the panel ranged from 10 to 52. The scores were then sectioned into tertiles (low, medium, and high), but no significant associations were found between Food Neophobia scores and hedonic ratings for the broths. The low acceptability of the broths and the panelists’ prior experience eating seaweed might have limited effects of the test participants’ food neophobia.

Future work should focus on developing greater flavor and testing soups with other ingredients since consumers do not usually consume broth alone. Shelf-life of broths should also be evaluated. Also, more information about the health benefits of seaweed and the economic impact of Maine farmed seaweed may help increase consumer interest in these healthful foods.

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