Beth L. Calder

Sensory and fatty acid analyses of two Atlantic species of Porphyra (Rhodophyta)

Sensory analyses were conducted to determine levels of consumer acceptability of Porphyra yezoensis, P. umbilicalis, and P. amplissima to select appropriate species for aquaculture development in Maine (USA). The subjects included children (n = 67) and adults (n = 84); the children participated in study design by helping to select the 9 point hedonic scale used in the affective sensory tests. Two substrates were used; Porphyra was baked in crackers and also used as a coating for popcorn. No significant differences (p > 0.5) in acceptability of one species over another were observed in either trial, which suggests that native Atlantic species of Porphyra such as P. amplissima and P. umbilicalis have developmental potential in foods for North American consumers. Fatty acids were analyzed in the taste test material and in freshly collected P. umbilicalis; eicosapentaenoic acid [EPA; 20:5 (n-3)] and palmitic acid were the most common fatty acids. Quantitative analysis of EPA determined that freshly collected (January 2005) P. umbilicalis contained 3.2 mg EPA g dry wt−1 (74 mg EPA 100 g fresh wt−1). This concentration is not high enough to make P. umbilicalis a primary source of daily omega-3 fatty acids, but the favorable n-3/n-6 ratio (2-3:1) in these species contributes to their nutritional value.

Comparison of Sodium Acid Sulfate to Citric Acid to Inhibit Browning of Fresh‐Cut Potatoes

Sodium acid sulfate (SAS) dip treatments were evaluated against a distilled water control and citric acid (CA) to compare its effectiveness in reducing enzymatic browning of raw, French-fry cut potatoes. Two separate studies were conducted with dip concentrations ranging from 0%, 1%, and 3% in experiment 1 to 0%, 2%, and 2.5% in experiment 2 to determine optimal dip concentrations. Russet Burbank potatoes were peeled, sliced, and dipped for 1 min and stored at 3 °C. Color, texture, fry surface pH, and microbiological analyses were conducted on days 0, 7, and 14. The 3% SAS- and CA-treated samples had significantly (p<0.0001) lower pH levels on fry surfaces than all other treatments. Both acidulants had significantly (p≤0.05) lower aerobic plate counts compared to controls in both studies by day 7. However, SAS appeared to be the most effective at the 3% level in maintaining a light fry color up to day 14 and had the highest L-values than all other treatments. The 3% SAS-treated fry slices appeared to have the least change in textural properties over storage time, having a significantly (p=0.0002) higher force value (kg force [kgf]) than the other treatments during experiment 1, without any signs of case-hardening that appeared in the control and CA-treated samples. SAS was just as comparable to CA in reducing surface fry pH and also lowering microbial counts over storage time. According to the results, SAS may be another viable acidulant to be utilized in the fresh-cut fruit and vegetable industry.

The Effectiveness of Ozone and Acidulant Treatments in Extending the Refrigerated Shelf Life of Fresh-Cut Potatoes

The objective of the study was to determine the effectiveness of acidulant dip treatments (with or without aqueous ozone) to reduce enzymatic browning and to extend the shelf life of fresh-cut potato slices during refrigerated storage (4 °C) for 28 d. Potato slices subjected to aqueous ozone (2 ppm) had significantly (P≤ 0.05) higher L-values and lower a-values, but ozone did not appear to have any effect on aerobic plate counts (APCs) or polyphenol oxidase (PPO) activity. NatureSeal (NS) and sodium acid sulfate (SAS) were the most effective acidulant treatments in reducing browning (significantly [P≤ 0.05] higher L-values, lower a-values, and browning index values) regardless of ozone treatment. NS and SAS also had lower PPO activity compared to other treatments on days 0 and 28, and significantly (P≤ 0.05) lower APCs (≤2.00 log CFU/g) over refrigerated storage. Therefore, the SAS treatment was comparable to NS, a commercially available product, and showed promise as an effective antibrowning dip to reduce browning and spoilage in fresh-cut potato products. Practical Application:  A 1% SAS dip treatment which included 1% citric and 1% ascorbic acid was found to be an effective antibrowning dip for fresh-cut potatoes along with NatureSeal®s PS-10, compared to other treatments. They were both effective in maintaining low microbial counts over refrigerated storage. Additionally, aqueous ozone washes (2 ppm) showed significant benefits to reduce browning; however, ozone did not affect microbial counts or PPO enzyme activity. Therefore, the SAS treatment could have potential use in the fruit and vegetable industry to reduce browning and spoilage in fresh-cut potato products.

Assessing the Food Safety Knowledge of University of Maine Students.

Foodborne illness is a global public health issue. Young adults may work in foodservice while they are university students, and their habits may later shape the practices and well-being of their children. The objective of this study was to establish baseline data and assess the food safety knowledge of 18- to 26-year-old Univ. of Maine students. Demographic questions and the previously validated Food Safety Knowledge Questionnaire (FSKQ) were placed online. Of 123 people who responded to the email recruitment notice, 104 Univ. of Maine undergraduates aged 18 to 26 years completed the survey. The average score among all participants was 60% correct (53 points out of a possible 89 points). Survey questions that required participants to identify common sources of foodborne pathogens had the lowest average percent correct (31%). Less than 50% of participants were able to correctly identify several high-risk foods, including sliced melon, raw sprouts, and unpasteurized fruit juice. Our findings indicate a need for educational programs for 18- to 26-year-old Univ. of Maine students in regards to common sources of foodborne pathogens and proper handling of fresh produce and that food safety knowledge among university students has not improved since publication of a national survey using the FSKQ in 2006. Effective educational programs are needed to ensure that young adults understand food risks and appropriate food handling practices.

Mechanical Separation of Green Crab (Carcinus maenas) Meat and Consumer Acceptability of a Value-Added Food Product

ABSTRACT Mechanical separation of green crab resulted in an average mince yield of 49.2%, with average moisture, ash, protein, and lipid contents of 81.0, 5.1, 10.4, and 1.4%, respectively. Mince from small crabs (< 55-mm carapace width) had significantly lower lipid contents and L* values than mince from large crabs (> 55 mm). The overall acceptability of green crab mince empanadas (fried, stuffed pastries) was rated between “like slightly” and “like moderately” by a consumer panel (n = 87), regardless of empanada formulation (30, 50, or 70% mince by filling weight). Additionally, 63% of respondents indicated they would “probably” or “definitely” buy the empanadas if available locally.

The effectiveness of antibrowning dip treatments to reduce after-cooking darkening in potatoes.

UNLABELLED After-cooking darkening (ACD) is an inherent and undesirable trait that develops in cooked potatoes. The objective of this study was to evaluate the effectiveness of sodium acid sulfate (SAS) dip treatments compared to other antigraying treatments and a control to reduce ACD in boiled, Katahdin potatoes. Dip treatments were applied for 3 min prior to boiling and included: 3% SAS, 3% citric acid (CA), 3% sodium acid pyrophosphate (SAPP), along with a distilled water control. SAS- and CA-treated potatoes had slightly, but significantly (P ≤ 0.05) higher b* and chroma values, which indicates a more intense yellow potato color, with less graying, compared to the control. SAS- and CA-treated potatoes also had significantly (P≤ 0.001) lower pH values for inner and outer potato surfaces than the control. No significant (P > 0.05) differences were detected for total phenolic or mineral contents among treatments. CA and SAPP samples had slightly, but significantly (P≤ 0.05) higher moisture contents than the control. Sensory test results showed no significant differences for color, aftertaste, or overall acceptability. However, CA-treated samples were rated significantly (P≤ 0.05) lower for flavor than all other treatments and panelists commented on sour notes. CA- and SAS-treated potatoes were scored slightly, but significantly lower for texture than other treatments due to a waxy outer layer. However, SAS was the most acidic dip treatment, but did not significantly affect flavor. Overall, results suggest that SAS was similarly accepted by consumers in comparison to CA and SAPP, which is the industry standard to reduce ACD. PRACTICAL APPLICATION After-cooking darkening (ACD) is an undesirable potato trait that occurs after potatoes have been processed. Sodium acid pyrophosphate (SAPP) has been used as the industry standard to reduce ACD. Sodium acid sulfate (SAS) treatments prior to boiling appeared to be comparable to SAPP and citric acid in effectiveness to reduce ACD. SAS did not negatively affect the flavor of boiled potato samples according to sensory results. The SAS treatment may be more beneficial for potatoes intended for potato salad products.

Effects of Chlorine Spray and Freezing on the Microbiological Quality of Maine Wild Blueberries

ABSTRACT This study examined the influence of two key processing steps, chlorine spray and freezing, on the microbiological characteristics of frozen wild blueberries. Home and garden sprayers were modified to approximate processing conditions. Samples were sprayed with either sterile water or 100 ppm chlorine solution and allowed 30, 60, 120, or 300 second contact times. Microbiological analyses of total aerobes and yeasts were conducted using FDA Standard Methods. ANOVA and Tukeys HSD multiple comparisons were used to evaluate effectiveness of all treatments. All treatments resulted in statistically significant (P # 0.05) reductions when compared to initial values. Duration of exposure was not statistically significant. However, no statistically significant difference between samples receiving sterile water or chlorinated water washes was detected. Chlorination and freezing produced a mean log reduction of 1.85 while sterile water and freezing resulted in a reduction of 1.28 logs.