Structure–activity relationships of acetylated flavone glycosides from Galeopsis ladanum L. (Lamiaceae)

Antioxidant activity, neuroprotective effect and acetylcholinesterase inhibitor activity were studied in acetylated flavones from Galeopsis ladanum L. (Lamiaceae), previously isolated and identified by UV-spectra, UPLC–MS/MS and ¹H-NMR spectroscopy. Structure–activity relationships of flavonoids have been determined in many antioxidant assays, generally focused on hydroxyl groups. In this study we have detected new interesting structure–activity relationships for the isolated flavonoids due to the acetylation of sugar moiety of these flavonoids. Methylation at 4′-OH and monoacetylation is beneficial to inhibiting AChE and shows a neouroprotective effect.     

Development of the Maillard reaction in foods cooked by different techniques. Intake of Maillard-derived compounds

Specific and non-specific Maillard reaction (MR) indices such as CIELab colour, browning measurement, furosine, hydroxymethylfurfural (HMF) and furfural, as well as the nutrient content, were analysed for commonly consumed dishes, to test the effects of different culinary treatment on dishes composed of the same ingredients. In addition, the consumption of early MR products (MRP), Amadori compounds, HMF and furfural from a normal serving of these dishes was calculated. As expected, recipes including frying, apart from their particular composition, led to significantly higher values of furosine and HMF, ranging from 4.40 to 175 and from 0.30 to 22.7 mg/kg, respectively; consequently they provided the highest levels of Amadori compounds and HMF intake (0.42–26.8 and 0.02–2.38 mg/serving, respectively). Even so, MRP intake/serving was not very high in comparison with levels reported in the bibliography on some individual foods typically studied in terms of MR development, suggesting that the culinary treatments used do not make a great contribution to the daily MRP consumption.     

The relationship between the composition and texture of conventional and low-fat frankfurters

The chemical composition, instrumental texture and sensory properties of eighteen conventional and three low-fat commercially produced frankfurters were analysed. The most important factors in defining the texture of the product were hardness and juiciness, these being related respectively to the percentage of protein and the fat/protein ratio in the frankfurter. Subsequently, using a basic formulation of soya protein and starch, different levels of fat (10 and 15%) and hydrocolloids [carrageenan, carboxymethylcellulose (CMC) and apple pectin] were tested. According to results from these trials, three low-fat formulations were chosen. The three low-fat sausages were a sausage with 15% fat and carrageenan (0.5%), a sausage with 10% fat and a combination of carrageenan (0.5%) and pectin (0.4%) and a sausage with 10% fat and a combination of carrageenan (0.5%) and CMC (0.1%). The sensory and instrumental texture attributes of the three low-fat and the standard sausages were investigated. Results indicated that low-fat (10%) frankfurters with a texture profile similar to standard frankfurters could be manufactured through the addition of mixtures of proteins and hydrocolloids. The combination of carrageenan with CMC or apple pectin is more efficient than the use of carrageenan alone as both combinations allow a higher reduction of fat, at the same time achieving a final texture well liked by consumers.     

HPLC flavonoid profiles as markers for the botanical origin of European unifloral honeys

The HPLC phenolic profiles of 52 selected unifloral honey samples produced in Europe were analysed to detect possible markers for the floral origin of the different honeys. Lime‐tree (five markers), chestnut (five markers), rapeseed (one marker), eucalyptus (six markers) and heather (three markers) honeys had specific markers with characteristic UV spectra. In addition, the flavanone hesperetin was confirmed as a marker for citrus honey, as well as kaempferol for rosemary honey and quercetin for sunflower honey. Abscisic acid, which had been reported to be a possible marker for heather honey, was also detected in rapeseed, lime‐tree and acacia honeys. Ellagic acid in heather honey and the hydroxycinnamates caffeic, p‐coumaric and ferulic acids in chestnut, sunflower, lavender and acacia honeys were also detected. The characteristic propolis‐derived flavonoids pinocembrin, pinobanksin and chrysin were present in most samples in variable amounts. © 2001 Society of Chemical Industry     

Spoilage of blood sausages morcilla de Burgos treated with high hydrostatic pressure

In this study, the microbial ecology of the blood sausage morcilla de Burgos, subjected to high hydrostatic pressure treatment (HPP), was studied by culture-dependent and -independent methods. Morcilla de Burgos is the most traditional and famous blood sausage in Spain. The producers are interested in extending its shelf-life in order to expand their market and to reduce losses attributed to spoilage. Sausage batter prior to stuffing and blood sausages HPP treated or not (control) were analyzed at 0, 9, 14, 21, 28 and 35 days of storage at 4 degrees C. Lactic acid bacteria, Pseudomonas spp. and aerobic mesophilic bacteria were investigated by traditional plating. PCR-denaturing gradient gel electrophoresis (DGGE) was used to analyze the DNA and the RNA extracted directly from the blood sausages, as well as bulk cells of LAB and Pseudomonas spp. The results showed that HPP improved the shelf life of morcilla de Burgos to 28 days in comparison with control samples. The populations responsible for spoilage, namely LAB, remained lower in HPP treated samples when compared with the control samples. Only at 35 days of storage they reached values of 10(8) cfu/g, leading to the spoilage of the product. Although, HPP affected the LAB population, they were able to recover the injury provoked by the treatment. Lastly, HPP seemed to affect differently LAB species detected. While Leuconostoc mesenteroides was completely inactivated by HPP, Weissella viridescens was able to recover and carry out the typical spoilage of the product. Pseudomonas spp. remained under detection level (<10(2) CFU/g) after the HPP treatment.     

Characterisation of Bobal and Crujidera grape cultivars,in comparison with Tempranillo and Cabernet Sauvignon: Evolution of leaf macronutrients and berry composition during grape ripening

We present characterisation data for two Spanish autochthonous grapevines, Bobal and Crujidera, in comparison with the well-known cultivars Tempranillo and Cabernet Sauvignon. Microsatellite markers were used for the molecular characterisation of Crujidera grapevines. Leaf macronutrient contents of the four cultivars were evaluated, as well as their changes at different vine developmental stages, and veraison was seen as the most suitable time to evaluate the nutritional status. Quantitative changes in some physiological parameters and the phenolic composition of the four grape varieties were measured during the last month of ripening. Polyphenols, tannins and anthocyanins increased with grape maturation, although the accumulation of these phenolic compounds and their patterns of evolution varied considerably with the cultivar. The biosynthetic potential of these grapes to produce resveratrol largely depended on the grape variety, with a remarkably high content found in Bobal berry skins.     

Differential effect of organic cultivation on the levels of phenolics,peroxidase and capsidiol in sweet peppers

BACKGROUND: Coincident with the changes in agricultural practices from conventional to organic, changes in the nutrient composition of fresh fruits and vegetables have been identified. The levels of peroxidase, total phenolics content, and capsidiol activity in organic as compared with conventional sweet pepper fruit were examined in this study. In order to avoid interferences of environmental factors on the studied parameters, the sweet peppers were grown (organically and conventionally) in a greenhouse under the same soil and climate conditions. RESULTS: Peroxidase was partially purified using the Triton X‐114 method and both organic and conventional peppers had the same isoenzymatic form. However, peroxidase activity in organic sweet peppers was higher than in conventional ones, in both maturity stages studied. The level of total phenolics compunds was also higher in organic than in conventional sweet peppers. With respect to the capsidiol activity, expressed as inhibition of fungus growth, it was not affected by the cultivation method at the green mature stage. However, at the red mature stage, organic sweet peppers showed higher capsidiol activity than those grown under the conventional system. CONCLUSION: Sweet peppers grown under organic culture have a maturity‐related response, with high levels of phenolic compounds, and peroxidase and capsidiol activity that contribute to disease resistance in organic farming. Copyright © 2007 Society of Chemical Industry     

Antioxidant properties and shelf‐life extension of fresh‐cut tomatoes stored at different temperatures

BACKGROUND: The feasibility of using modified atmosphere packaging (5 kPa O₂ + 5 kPa CO₂) to maintain the antioxidant properties of fresh‐cut tomatoes during shelf‐life was assessed through storage at different temperatures (5, 10, 15 and 20 °C). Health‐related compounds, antioxidant capacity, microbiological counts, physicochemical parameters and in‐package atmosphere of tomato slices were determined. RESULTS: Initial lycopene, vitamin C and phenolic contents and physicochemical parameters of tomato slices were well maintained for 14 days at 5 °C. Lycopene and total phenolic contents were enhanced over time in tomato slices stored at 15 and 20 °C. However, this increase in antioxidant compounds of fresh‐cut tomatoes during storage may be associated with excessive amounts of CO₂ (R² = 0.5679–0.7328) in the packages due to microbial growth. Although keeping tomato slices at temperatures above 10 °C increased their antioxidant content, the shelf‐life of the product was reduced by up 4 days. CONCLUSIONS: A storage temperature of 5 °C is appropriate for maintaining the microbiological shelf‐life of fresh‐cut tomatoes for up to 14 days and also allows the antioxidant properties of tomato slices to be retained over this period, thus reducing wounding stress and deteriorative changes. Copyright © 2008 Society of Chemical Industry     

Effect of the packaging method and the storage time on lipid oxidation and colour stability on dry fermented sausage salchichón manufactured with raw material with a high level of mono and polyunsaturated fatty acids

The effects of fatty acid composition, two packaging methods (vacuum and 20% CO₂/80% N₂) and storage under refrigeration for 210 days were evaluated on a dry fermented sausage (salchichón), manufactured with raw material enriched in monounsaturated or polyunsaturated fatty acids. Fatty acid composition was determined on sausage mixtures and on ripened sausages and lipid oxidation and colour stability was determined on ripened sausage at different times during storage. The modification of fatty acid composition of the sausages raised the nutritional quality, slightly affecting the colour properties. Dry fermented sausages enriched in polyunsaturated and monounsaturated fatty acids presented higher lipid oxidation values than the control ones. Both packaging methods (vacuum and 20% CO₂/80% N₂) during 210 days of chilled storage had minor effects on the colour and the lipid oxidation stability.     

Changes of health-related compounds throughout cold storage of tomato juice stabilized by thermal or high intensity pulsed electric field treatments

The effect of high intensity pulsed electric fields (HIPEF) processing (35 kV/cm for 1500 μs in bipolar 4-μs pulses at 100 Hz, with an energy density of 8269 kJ/L) on the main bioactive compounds and antioxidant capacity of tomato juice was investigated and compared to heat pasteurization (90 °C for 1 min or 30 s) having the fresh juice as a reference. HIPEF and heat treated tomato juices showed higher lycopene and lower vitamin C levels than the untreated juice. However, no significant changes in the total phenolic content and antioxidant capacity were observed between treated and fresh juices just after processing. Lycopene, vitamin C and antioxidant capacity of both treated and untreated juices decreased exponentially during storage following a first order kinetics (R² = 0.763–0.987), whereas tomato juices maintained their initial phenolic content. HIPEF-treated tomato juice maintained higher lycopene and vitamin C content than the thermally treated juices during the storage time. Hence, the application of HIPEF may be appropriate to achieve nutritious and fresh like tomato juice.

Industrial relevance

HIPEF processing can lead to tomato juice with higher nutritional value than that thermally processed. HIPEF-treated (35 kV/cm for 1500 μs with 4-μs bipolar pulses at 100 Hz, energy input of 8269 kJ/L) tomato juice shows greater lycopene, vitamin C and antioxidant capacity just after the treatment and during the storage time than heat treated (90 °C­30 s and 90 °C­60 s) tomato juice. Therefore, HIPEF technology is a feasible alternative to thermal treatment to obtain tomato juice with a high presence of health-related compounds.