Sujinda Sriwattana

Influence of Package Visual Cues of Sweeteners on the Sensory-Emotional Profiles of Their Products

Substantial evidence suggests influence of color, physical state, and other extrinsic features on consumer perception and acceptability of food products. In this study, 560 subjects evaluated liking and emotional responses associated with 5 sweeteners (sucralose, stevia, saccharin, aspartame, and sucrose) under 2 eliciting conditions: control (brand name only) and informed (brand name/packet image), to assess impact of the packet color. For a given condition, 5 identical tea samples each labeled with a sweetener type were rated for sweetness and overall liking (9-point) and emotions (5-point). Nonsignificant interactions between eliciting condition and sweetener type were found for liking attributes and emotions (except peaceful), indicating their independent effects. However, overall differences existed among sweetener types and eliciting conditions based on both hedonic and emotional responses (MANOVA, P < 0.05), suggesting modulating effects of packet color on sweetener type in the sensory-emotion space. The sensory-emotion profile for sucrose was separate from that of nonnutritive sweeteners, with statistically significant Mahalanobis distances among sample centroids. Increases in positive emotion intensities contrasted with a decrease in negative emotion intensities were observed for some sweeteners moving from the control to informed condition. Sweetness liking was strongly correlated with the emotion satisfied (sucralose, saccharin) only in the control condition, whereas it was strongly correlated with the emotions pleased and satisfied (stevia), disgusted (aspartame), and satisfied (sucrose) only in the informed condition. Overall, results suggested that sensory liking and emotions during the consumption experience are related not entirely to the type of sweetener, but also the color of the packet.

Analysis of Duplicated Multiple-Samples Rank Data Using the Mack–Skillings Test

Appropriate analysis for duplicated multiple-samples rank data is needed. This study compared analysis of duplicated rank preference data using the Friedman versus Mack-Skillings tests. Panelists (n = 125) ranked twice 2 orange juice sets: different-samples set (100%, 70%, vs. 40% juice) and similar-samples set (100%, 95%, vs. 90%). These 2 sample sets were designed to get contrasting differences in preference. For each sample set, rank sum data were obtained from (1) averaged rank data of each panelist from the 2 replications (n = 125), (2) rank data of all panelists from each of the 2 separate replications (n = 125 each), (3) jointed rank data of all panelists from the 2 replications (n = 125), and (4) rank data of all panelists pooled from the 2 replications (n = 250); rank data (1), (2), and (4) were separately analyzed by the Friedman test, although those from (3) by the Mack-Skillings test. The effect of sample sizes (n = 10 to 125) was evaluated. For the similar-samples set, higher variations in rank data from the 2 replications were observed; therefore, results of the main effects were more inconsistent among methods and sample sizes. Regardless of analysis methods, the larger the sample size, the higher the χ(2) value, the lower the P-value (testing H0 : all samples are not different). Analyzing rank data (2) separately by replication yielded inconsistent conclusions across sample sizes, hence this method is not recommended. The Mack-Skillings test was more sensitive than the Friedman test. Furthermore, it takes into account within-panelist variations and is more appropriate for analyzing duplicated rank data.

Antimicrobia activity of garlic (Allium sativum L.) and holy basil (Ocimum sanctum L.) essential oils applied by liquid vs. vapour phases

Antimicrobial activity of garlic (Allium sativum L.) and holy basil (Ocimum sanctum L.) essential oils (GEO and HBEO, respectively) was evaluated in liquid vs. vapour phases. Diallyl disulphide and diallyl trisulphide in GEO while eugenol, caryophyllene and methyl eugenol in HBEO were predominant active compounds. Individually, GEO was highly effective in the vapour phase, showing the greatest antimicrobial activity (P ≤ 0.05) against Bacillus cereus and Staphylococcus aureus with complete inhibition, followed by Salmonella typhimurium and Pseudomonas fluorescens, but had no effect on Escherichia coli, Lactobacillus plantarum or Listeria monocytogenes. The combined GEO:HBEO (a 1:1 ratio) at 30 lL demonstrated inhibitive activity against all bacteria tested with complete inhibition against B. cereus and S. aureus. Minimum bactericidal concentration (MBC) of the combined oil was <0.4% v/v, except for P. fluorescens requiring a higher MBC (1.5%, v/v). This study demonstrated potential of the combined GEO:HBEO to be used for food preservation applications.

Structural modification of swai-fish (Pangasius hypophthalmus)-based emulsions containing non-meat protein additives by ultra-high pressure and thermal treatments

ABSTRACT Swai-fish emulsions containing fermented soybeans (thua nao and rice-koji miso) were pressurized at 600 MPa for 20 min or heated at 72°C for 30 min. The fish batters were blended with soy protein isolate (SPI) or whey protein concentrate (WPC) to stabilize the emulsions. The processed fish emulsions were then subjected to physical, chemical and microbiological examinations. The results of gel strength and water-holding potential showed that SPI addition yielded higher impact on these properties than WPC addition, which was also confirmed by the interactions between SPI and native fish proteins depicted by electrophoregrams. The frequency profiles suggested that the heated gels had a greater storage and loss moduli than pressurized gels, while pressurized WPC set-gel displayed larger loss tangent (the predominance of viscous moiety) than those pressurized SPI set-gel. High bacteria and spore counts of B. subtilis (residual of the thua nao) were observed in both pressurized and heated fish-based emulsions.

Comparison of Ultrasonic Extraction with Conventional Extraction Methods of Phenolic Compounds in Longan (Euphoria longana Lamk.) Seed

Three different extraction methods – hot water (HWE), ethanol (EE) and ultrasonic-assisted water extraction (UAE) – were evaluated for extraction of phenolic compounds in longan (cultivar Edor) seed. The findings indicated that longan seed extracts contained three major phenolic compounds, analyzed by HPLC, including gallic acid, corilagin and ellagic acid. The content of total polyphenolic compounds and antioxidant activities was determined using the Folin-Ciocalteu method and the DPPH assay, respectively. Longan seed extraction by HWE contained the highest yield, total polyphenol content and antioxidant activities (42.80%, 41.250mg gallic acid/g and IC50 = 0.017 mg/ ml, respectively). UAE produced a higher yield than EE, but lower than HWE, with the lowest extraction time. Moreover, gallic acid content (16.55 mg/g) and corilagin content (35.62 mg/g) extracted by UAE were higher than those of HWE and EE. Ellagic acid content obtained from UAE was significantly (P<0.05) higher than that from EE, but not significantly different from that of HWE. The application of UAE could provide an alternative method for extraction of photochemical from longan seeds.