The following is an adaptation of a poster presented at the 2001 ASHS Meeting, Sacramento, California.

INTRODUCTION

Americans purchase over 10.5 billion sandwiches each year with hamburgers and cheeseburgers accounting for more that 50 percent of the total. Additionally, Mexican food is a major variety of food sold in fast food restaurants. In an effort to increase nutrient density of fast food entrees, sensory evaluations were conducted to determine consumer acceptance of spinach as a replacement for iceberg lettuce on hot and cold sandwiches and tacos. Hamburger, club submarine sandwich and taco ingredients were purchased from nationally recognized fast food restaurants. Fresh, curly leafed spinach was washed, central vein removed and shredded to resemble the shape of the iceberg lettuce supplied by the restaurant. Entrées were assembled with either iceberg lettuce or spinach as an ingredient. Hamburgers (n=43), sub sandwiches (n=112), and tacos (n = 57) were evaluated on different days at 5 different sites. Untrained taste panelists received either two samples with lettuce and one with spinach or two samples with spinach and one with lettuce. Panelists rated each sample using a Hedonic scale of 1 (like extremely) to 5 (dislike extremely). Statistical analyses of data were conducted using ANOVA for comparing group ratings. Data indicated that order of presentation (2 lettuce, 1 spinach or 2 spinach, 1 lettuce) had no significant effect on acceptability. No significant differences were found when spinach replaced lettuce on either the hamburger or submarine sandwich. When data from hot and cold sandwiched were combined, the Hedonic rating for all spinach samples and all lettuce samples was 2.19 ± 0.07 (mean ± SE) and 2.21 ± 0.07, respectively. For tacos, no significant difference in acceptability was found when panelist received 1 lettuce and 2 spinach tacos (1.96 + 0.17 and 2.07 + 0.14, respectively). However, panelist significantly preferred the tacos with spinach when given 2 lettuce and one spinach taco (2.34 + 0.14 and 1.86 + 0.17, respectively (P<0.05)). The results indicate that the acceptability of sandwiches made with spinach was equal to those made with lettuce.

PURPOSE

To determine consumer acceptance of spinach as a replacement for iceberg lettuce on fast food entrees.

MATERIALS AND METHODS

Ingredients were purchased form three nationally recognized fast food restaurant chains. Hamburger patties and buns were cooked by the restaurant and transported to the sensory evaluation laboratory in temperature-controlled containers. Sub sandwich ingredients were refrigerated until assembly. Taco ingredients were prepared according to restaurant specifications. Entrées were assembled according to restaurant specifications immediately before serving. For each entrée, samples were assigned random numbers for identification. Each entrée contained the following ingredients:

Taste panelists were recruited from University of Arkansas students, faculty and staff and from a local high school. Forty-three (43) individuals participated in the hamburger taste test, 112 in the submarine sandwich test and 57 individuals in the taco taste test. Panelists were divided into two groups. One group received two (2) samples with lettuce and one (1) with spinach while the other group was given two (2) samples with spinach and one (1) with lettuce.

Oral and written tasting instructions were provided to each panelists. Distilled deionized water and unsalted cracker were provide to cleanse the palate between samples. Panelists were asked to rate each sample using a Hedonic scale from 1 (like extremely) to 5 (dislike extremely). Tasters were instructed to taste a sample, rate it, and then cleanse the palate before going to the next sample.

STATISTICAL ANALYSIS

Statistical analyses of Hedonic rating data were conducted using analysis of variance (ANOVA).

RESULTS

Hot and Cold Sandwiches

Data indicate that taste panelists found hamburgers (Table 1) and submarine sandwiches (Table 2) made with spinach equally likeable as sandwiches made with iceberg lettuce. No statistical differences were found between groups. When sandwich data were combined (hamburger and sub, n = 145), the results remained unchanged. Consumers found hot and cold sandwiches made with spinach as acceptable as those made with lettuce (2.19 + 0.07 and 2.21 + 0.07, respectively).

Table 1. Hedonic rating of hamburgers made with spinach or lettuce.

Table 2. Hedonic rating of submarine sandwiches made with spinach or lettuce

Figures 1 & 2. Comparison of spinach and lettuce on hamburgers (below) and submarine sandwiches (right).

Tacos

A total of 57individuals participated in the taco taste test. Group 1 received 2 tacos with lettuce and one with spinach (2L/1S). Group 2 received 1 taco with lettuce and two with spinach (1L/2S). Group l rated tacos with spinach significantly (P<0.05) more likeable than tacos with lettuce (Table 3). No significant difference between tacos with lettuce or spinach was observed for Group 2. Further, when data from Group 1 and 2 were combined, consumers rated tacos with spinach and tacos with lettuce equally acceptable.

Table 3: hedonic rating of Tacos made with spinach or lettuce

^ab Means not sharing a common superscript letter are significantly different (P<0.05)

Rating scale: 1 = like extremely; 2 = like moderately; 3 = neither like nor dislike; 4 = dislike moderately; 5 = dislike extremely

Table 4. Nutrient Comparison of Fresh Iceberg Lettuce and Fresh Savoy Spinach

• Nutrient composition was calculated for comparison purposed only using ingredient data obtainedfrom the USDA database at: "http://www.nal.usda.gov/fnic/".
• Percent Difference = (Lettuce – Spinach)/Lettuce x 100

CONCLUSIONS

1. Americans consumption of fast food continues to increase. By making a small change in ingredients, the dietary intake of essential nutrients such as vitamin A, vitamin C and folate can be increased in fast food consumers. Further, the content of the phytochemical, lutein, is much higher in spinach than in lettuce.

2. Consumers rated sandwiches made with spinach as likeable as those made with iceberg lettuce.

3. Consumers rated tacos made with spinach as likeable as those made with iceberg lettuce.

4. Data indicate that consumers will accept spinach as a replacement for iceberg lettuce in fast food entrees. Given the volume of sandwiches and Mexican food entrees consumed each year, this small, acceptable change in ingredients could have a significant positive impact on the nutrition and health status health of fast food consumers.