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.     

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.     

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     

Chapter 3: Double‐Embryo,High‐Protein,High‐Oil Maize Produced Using a Cytokinin‐Based Flower Rescue

ABSTRACT: Maize is an important staple of human diets and animal feed.Improving the nutritional profile for both of these purposes is a desirable research focus and agricultural endpoint. Many mechanisms have been used to improve maize protein and oil content, including selective breeding to introgress desirable traits (Quality Protein Maize), introducing single natural or synthetic genes expressing desired traits, changing signal sequences (high methionine maize), and modifying metabolic pathways (high‐lysine maize, see Chapter 6). A novel approach was used to indirectly increase protein and oil content ( Young and others 2004 ). Maize produces unisexual florets. Within the maize spikelet,the meristem gives rise to an upper and lower floret and male (tassel)‐ and female (ear)‐specific florets are borne on separate inflorescences.The lower floret of each ear spikelet is aborted early in its devel‐opment,leaving the upper floret to mature as the only female floret.Expression of a bacterial cytokinin‐synthesizing isopentenyl transferase (IPT) enzyme,under the control of the Arabidopsis senescence‐inducible promoter SAG 12 (senescence associated gene), blocked the abortion of the lower floret and resulted in 2 functional florets per spikelet.The pistil in each floret was fertile,but the spikelet produced just 1 kernel composed of a fused endosperm with 2 viable embryos.The 2 embryos were genetically distinct, indicating that they had arisen from independent fertilization events. The embryo contains most of the protein and oil in the kernel and kernels that contained 2 embryos have more protein than conventional maize.The presence of 2 embryos in a normal‐sized kernel leads to displacement of endosperm growth, resulting in kernels with an increased ratio of embryo to endosperm content. The end result is maize with more protein and oil and less carbohydrate ( Young and others 2004 ).     

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.     

Process optimisation for a ready‐to‐serve breakfast smoothie from a composite milk–sorghum base

A composite milk and sorghum‐based smoothie containing varying levels of sorghum flour (2–4% w/w), sugar (9–11% w/w) and pectin (0.2–0.4% w/w) was optimised by response surface methodology on the basis of sensory (colour and appearance, flavour, consistency, sweetness and overall preference) and physical (viscosity, sedimentation and wheying off) attributes. Flour and pectin levels influenced the flavour, consistency, viscosity and sedimentation significantly. Sugar helped to increase the overall preference and had a positive correlation with sedimentation. An optimised smoothie composition of acceptable quality was obtained with 2.79% (w/w) germinated sorghum flour (GSF), 10.30% (w/w) sugar and 0.35% (w/w) pectin.     

Cyclodextrin and methacrylic acid octyl phenols poly(ethylene oxide) ester‐induced synergistic effect in a novel poly(AM‐co‐A‐β‐CD‐co‐AE) polymer

Owing to superior properties such as temperature resistance and salt tolerance etc., modified polyacrylamide (PAM) as one of the main injected polymers has been widely investigated to enhance oil production in reservoirs. Herein, a novel poly(AM‐co‐A‐β‐CD‐co‐AE) polymer was synthesized by utilizing β‐CD and AE to copolymerize with AM and characterized by FT‐IR and SEM. Furthermore, the temperature resistance and salt tolerance of poly(AM‐co‐A‐β‐CD‐co‐AE) polymer were explored. The results showed that the presence of the poly(AM‐co‐A‐β‐CD‐co‐AE) polymer better achieved temperature resistance and salt tolerance properties than is the case with PAM, which has potential application for enhancing oil recovery in the high‐temperature and high‐mineralization oilfield. On the other hand, the inhibition performance of poly(AM‐co‐A‐β‐CD‐co‐AE) polymer as a corrosion inhibitor was evaluated by SEM and electrochemical techniques. SEM observations of the carbon steel surface confirmed the protective role of the corrosion inhibitor. The results of potentiodynamic polarization and EIS measurements on the corrosion inhibition of carbon steel samples in 0.5 M sulfuric acid solutions revealed that the highest inhibition efficiency of it over 90% was obtained, indicating poly(AM‐co‐A‐β‐CD‐co‐AE) polymer acts as a more efficient corrosion inhibitor for carbon steel.     

Metabolic Changes during the Pu‐erh Tea Pile‐Fermentation Revealed by a Liquid Chromatography Tandem Mass‐Spectrometry‐Based Metabolomics Approach

In the current study, liquid chromatography‐mass spectrometry combined with multivariate statistical analyses was employed to investigate the time‐varying biochemical changes during the pile‐fermentation process with the emphasis on the active ingredients to clarify the manufacturing process of ripened pu‐erh tea as a whole. The metabolite profiles of different manufacturing processes were unique and could be distinguished with the aid of principal component analysis. Furthermore, partial least‐squares discriminant analysis revealed a pairwise discrimination between the raw material group and pile‐fermentation process groups or the final product group, and 48 differential metabolites with variable importance in the projection value greater than 1 were identified, which was confirmed by the subsequent hierarchical cluster analysis. These results highlight our current understanding of the exact changing process of the bioactive compounds during the pile fermentation, and the global change of these bioactive compounds provides the special flavor, taste, and health promoting effects of ripened pu‐erh tea.