Development of a long‐life vacuum‐packaged ready‐to‐eat meat product based on a traditional Portuguese seasoned meat

Carne do alguidar is a Portuguese traditional pork fried meat, usually manufactured for self‐consumption purposes. This study developed a ready‐to‐eat (RTE) meat product, to meet today's consumers’ convenience, manufactured at the industrial scale evaluating its quality and shelf life, assessing the effect of vacuum packaging and the use of an antioxidant (50 ppm BHT) to enhance oxidative stability. Physicochemical and microbiological parameters were assessed, and a sensory analysis was performed. Interestingly, no significant differences were recorded between control (non‐BHT) and antioxidant (BHT) samples. Microbiological counts remained at low levels throughout the storage period, ensuring the product's required microbiological quality. At later storage stages, higher values of thiobarbituric acid‐reactive substances arose and off flavours and aromas were perceived. Still, overall appreciation was not affected until 12 months of storage and a significant depreciation was perceived only after 15 months. Fibrousness and rising of off flavours were negatively correlated with overall appreciation.     

Application of a check‐all‐that‐apply question for the evaluation of strawberry cultivars from a breeding program

BACKGROUND: Traditionally, breeding research has been focused on increasing yield and fruit size, improving resistance to diseases, behaviour during transport and increasing postharvest shelf‐life. However, consumers' liking is one of the biggest challenges for strawberry breeding programs. In this context, the aim of the present work was to evaluate the application of a check‐all‐that‐apply (CATA) question to study consumers' perception of new strawberry cultivars. RESULTS: Average liking scores were low for a highly appreciated product like strawberries, which could be explained considering unfavourable weather conditions prior to harvest. However, despite the small differences in overall liking scores, significant differences were found in the frequency in which 14 out of the 22 terms of the CATA question were used to describe samples. This suggests that the evaluated CATA question was able to detect differences in consumers' perception of the sensory characteristics of the evaluated cultivars. Moreover, a significant correlation was found between laboratory analyses (firmness, colour, soluble solids and acidity) and consumers' responses to the CATA question, which indicates their validity. CONCLUSIONS: Considering results from the present study, the use of CATA questions could be a simple and interesting methodology to gain insight into consumers' perception of different fruit cultivars. Copyright © 2010 Society of Chemical Industry     

Oil‐in‐Water Emulsion Exhibits Bitterness‐Suppressing Effects in a Sensory Threshold Study

Little is known about how emulsion characteristics affect saltiness/bitterness perception. Sensory detection and recognition thresholds of NaCl, caffeine, and KCl in aqueous solution compared with oil‐in‐water emulsion systems were evaluated. For emulsions, NaCl, KCl, or caffeine were dissolved in water + emulsifier and mixed with canola oil (20% by weight). Two emulsions were prepared: emulsion 1 (viscosity = 257 cP) and emulsion 2 (viscosity = 59 cP). The forced‐choice ascending concentration series method of limits (ASTM E‐679‐04) was used to determine detection and/or recognition thresholds at 25 °C. Group best estimate threshold (GBET) geometric means were expressed as g/100 mL. Comparing NaCl with KCl, there were no significant differences in detection GBET values for all systems (0.0197 ‐ 0.0354). For saltiness recognition thresholds, KCl GBET values were higher compared with NaCl GBET (0.0822 ‐ 0.1070 compared with 0.0471 ‐ 0.0501). For NaCl and KCl, emulsion 1 and/or emulsion 2 did not significantly affect the saltiness recognition threshold compared with that of the aqueous solution. However, the bitterness recognition thresholds of caffeine and KCl in solution were significantly lower than in the emulsions (0.0242 ‐ 0.0586 compared with 0.0754 ‐ 0.1025). Gender generally had a marginal effect on threshold values. This study showed that, compared with the aqueous solutions, emulsions did not significantly affect the saltiness recognition threshold of NaCl and KCl, but exhibited bitterness‐suppressing effects on KCl and/or caffeine.     

Extending the shelf‐life of bananas with 1‐methylcyclopropene and a chitosan‐based edible coating

BACKGROUND: The marketability of bananas over long distances has been limited due to their highly perishable nature and sensitivity to ethylene. To increase the shelf‐life several alternatives have been tested in attempts to maintain quality characteristics. We evaluated the effects of 1‐methylcyclopropene (SmartFresh^SM, 1‐MCP) and a chitosan‐based edible coating (FreshSeal^®, EC), applied alone or combined, on bananas at ripeness stage 3. All fruits were stored for 8 days at 22 °C, 85% RH. Color development, weight loss, firmness, physiological, sensory and chemical variables were evaluated. RESULTS: After 3 days, control and EC‐treated fruits were completely yellow (°Hue = 90), while 1‐MCP treated fruits alone and combined with EC were still showing some green colorations on tips and neck of fingers. After 7 days, fruits treated with the combination (EC + 1‐MCP) reached a Hue value of 90. Firmer fruits were observed with 1‐MCP alone or combined with EC. A decrease of 0.15% titratable acidity and an increase of 8°Brix were observed in all treatments during the experiment. The incidence of sugar spots was delayed and diminished on fruits treated with 1‐MCP either alone or combined. Sensory results showed no adverse effects by using the 1‐MCP or the edible coating. CONCLUSION: The combined treatment of EC + 1‐MCP could be used to extend the commercial life of bananas for up to four more days. Copyright © 2009 Society of Chemical Industry     

Aptamer‐Based SERS Detection of Lysozyme on a Food‐Handling Surface

Undeclared food allergens due to cross contamination of processing equipment is a leading cause for food product recalls. Therefore, there is a great need for developing rapid and sensitive methods to detect food allergens. In this paper, an aptamer highly specific to egg white lysozyme was coupled to dendritic silver nanoparticles in order to perform surface enhanced Raman spectroscopy (SERS). The procedure was successfully tested in water and on a stainless steel food‐handling surface. The lowest detectable concentration for lysozyme was 0.5 μg/mL in water and 5 μg/mL on a stainless steel food‐handling surface. Principal component analysis shows a significant change in SERS spectra when lysozyme was present, suggesting the successful capture of lysozyme by the aptamer. Quantification of lysozyme target was also shown from 0 to 6 μg/mL, that is, 0, 0.5, 2, 6 μg/mL. Overall method took less than 40 min. The developed method can be extended to detect other food allergens using specific aptamers.     

The Sweetness Concentration‐Response of R,R‐Monatin,a Naturally Occurring High‐Potency Sweetener

Abstract: Monatin, known by the common and usual name arruva, is a zero‐calorie, high‐potency sweetener naturally occurring in the plant Sclerochiton ilicifolius A.Meeuse. The sweetness concentration‐response (C‐R) behavior of the most potent isomer (R,R‐) in room‐temperature (21 °C) water was determined using two‐alternative forced choice discrimination tests with a minimum of 69 tasters. Results were processed by a method previously published to obtain isosweet concentrations of sucrose for 8 monatin concentrations up to 240 mg/L. These were used to construct a C‐R plot. The equation for the resultant hyperbolic curve relating sucrose equivalent (SE,%) to monatin concentration ([monatin], mg/L) was SE = 26.7 ×[monatin]/(69.6 +[monatin]). R,R‐monatin has a potency above 3000 at 5% sucrose equivalent, making it one of the most potently sweet naturally occurring substances known. Practical Application: Monatin is a naturally occurring, zero‐calorie, high‐potency sweetener. We have measured the sweetness of monatin over a range of concentrations. This information will help developers of zero‐, low‐ and reduced‐calorie products formulate with monatin.     

Degradation of N‐(1‐Deoxy‐d‐xylulos‐1‐yl)glycine and N‐(1‐Deoxy‐d‐xylulos‐1‐yl)proline using thermal treatment

The formation and degradation of N‐(1‐Deoxy‐d ‐xylulos‐1‐yl)glycine and N‐(1‐Deoxy‐d ‐xylulos‐1‐yl)proline, derived from the secondary amine Maillard reaction in xylose‐amino acid model solutions, were detailed in this study. The identification and quantitative analysis of N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)glycine and N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)proline were carried out using high‐performance anion‐exchange chromatography and high‐performance liquid chromatography. The formation of intermediate and advanced products derived from N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)glycine and N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)proline was also tested using an UV‐Vis spectrophotometer to gain a better comparing of the degradation process of the two important Maillard reaction products using thermal treatment. Results showed that the degradation of N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)glycine was more significant than N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)proline. Moreover, xylose was tested in the degradation products of both N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)glycine and N‐(1‐Deoxy‐d‐ xylulos‐1‐yl)proline, which indicated that the degradation of N‐substituted 1‐amino‐1‐deoxyketoses was a reversible reaction to form reducing sugar.