Biochemical changes in cut vs. intact lamb's lettuce (Valerianella olitoria) leaves during storage

Consumers are oriented towards fresh-cut vegetables that provide phytonutrients useful for preventing stress-related diseases. The aim of this work was to evaluate the cut operations on the quality changes of lamb's lettuce ( Valerianella olitoria L.) cv. Trofy during storage at 4 °C for 8 days. Results showed that chlorophyll and carotenoids reduction was observed after 8 days of storage. In both treatments, total carotenoids after 8 days decreased from 20 to 16 mg g⁻¹ FW. Free and total phenols increased with storage in both treatments. Total phenols were 23% higher in control (32 μmol g⁻¹ FW) compared to cut leaves (25 μmol g⁻¹ FW) after 8 days of storage. Anthocyanins increased after 8 days and reached 30 mg 100 g⁻¹ FW without significant difference between treatments. Ascorbic acid (AsA) and dehydroascorbic (DHA) acid increased in cut leaves compared to control. After 1 day AsA concentration was 3 300 nmol g⁻¹ FW in cut leaves, while in control leaves was 1 500 nmol g⁻¹ FW. Analogously AsA + DHA was higher in cut leaves, 4 100 nmol g⁻¹ FW, while in control leaves the mean was 3 000 nmol g⁻¹ FW. After 5 days of storage the values of AsA returned to initial values, while AsA + DHA were lower.     

Phenolic content and profiles of selected wild fruits of Zimbabwe: Ximenia caffra, Artobotrys brachypetalus and Syzygium cordatum

The phenolic compound content and profiles of three wild fruits found in Zimbabwe were tentatively identified using the traditional colorimetric methods and high-performance liquid chromatography (HPLC). The fruits assayed were: Ximenia caffra , Artobotrys brachypetalus and Syzygium cordatum . Ximenia caffra fruit peels contained the highest amounts of total phenolics amounting to 1205 μg g⁻¹ in fresh weight, flavonols amounting to 27 μg g⁻¹ and phenolic acids on HPLC tentative identification showed higher concentrations compared with the profiles of the other fruits. Syzygium cordatum fruit peels contained the least amounts of phenolics amounting to 20 μg g⁻¹, flavonols amounting to 8 μg g⁻¹ and phenolic acids' HPLC profiles showed low concentrations. Comparing the peels and pulps of all the fruits, we detected more total phenolics in the peels of X. caffra as high as 1205 μg g⁻¹ and the pulps had 228 μg g⁻¹, more flavonols and phenolic acids while the peels of S. cordatum fruits contained the least with a total phenolic acid content of 20 μg g⁻¹, and had more flavonols in the pulps than the peels, 11 μg g⁻¹ and 8 μg g⁻¹, respectively. Ximenia caffra contained 1.2% and about 1% dry weight condensed tannins in peels and pulps, respectively. In S. cordatum we detected 0.2% and 0.3% dry weight condensed tannins in the peels and pulps, respectively.     

Selenium content in selected products of animal origin and estimation of the degree of cover daily Se requirement in Poland

The aim of the study was to determine Se concentration in selected products of animal origin (dairy products, pork, beef, chicken, giblets, fish, eggs) and to estimate the degree to which these products cover daily Se requirement in humans. Selenium concentrations were determined using the spectrofluorometric method. Mean Se concentration in the milk, yoghurt, kefir, and probiotic drinks was 0.020 μg mL⁻¹, 0.010 μg mL⁻¹, 0.012 μg mL⁻¹ and 0.012 μg mL⁻¹, respectively. Selenium concentration in cheese ranged 0.022–0.088 μg g⁻¹ wet weight. The average selenium content of meat ranged from 0.064 (beef) to 0.094 (chicken) μg g⁻¹ w.w. The mean Se content of giblets (liver: 0.307–0.401 μg g⁻¹ w.w.) was significantly ( P  < 0.05) higher than in meat. The concentration of Se depends on fish species and in our study it ranged from 0.136 ± 0.023 (flounder) to 0.282 ± 0.024 μg g⁻¹ w.w. (mackerel). The results obtained show that the analysed food provides 22.8% of the daily selenium requirement. Considering that animal products account for 40–45% of the diet daily selenium intake averages 33–37 μg.     

Influence of pre-treatments on microbial load of stored dehydrated onion slices

Onions slices were pre-treated in potassium meta-bisulphite (KMS) and sodium chloride with different concentration levels to study the microbial load of tray and greenhouse-dried onion slices up to 6 months of storage. Data were analysed as per procedure of one-way classified anova using DMRT of AgRes statistical package for bacteria, yeast, fungi and Lactobacilli . Results revealed that in almost all samples, permissible levels of bacteria [18.33 × 10¹ colony-forming units (CFU) per gram], yeast (ND), fungi (0.5 × 10¹ CFU g⁻¹) and Lactobacilli (0.25 × 10¹ CFU g⁻¹) were observed after 5 months of storage. All the samples were also found to be free from Escherichia coli and no Mac Conkey growth was noticed. Onion slices pre-treated in 0.25% and 0.50% KMS and dried in tray and greenhouse, respectively, were found best after 6 months of storage period.     

Methyl anthranilate content in Italian citrus honeys determined by HS-SPME-GC

An headspace solid phase microextraction-gas chromatography (HS-SPME-GC) method, previously developed and validated, was applied to the determination of the methyl anthranilate (MA) content of 75 Italian citrus honeys (11 of lemon, 44 of orange and 20 of Citrus spp.). Twenty-four samples were purchased on the local market and 51 were provided by CRA-API ( Consiglio Nazionale per la Ricerca e Sperimentazione in Agricoltura-Istituto Nazionale di Apicoltura e Bachicoltura ) (Bologna, Italy). All the samples had a MA content above the limit of detection (LOD) (0.149 μg g⁻¹) of the analytical method. The concentration range was between 0.46 and 2.52 μg g⁻¹ and the overall average MA content was 1.19 μg g⁻¹. The honeys with the highest mean MA content were the orange honeys followed by Citrus spp. and lemon (1.29 ± 0.461, 1.12 ± 0.511 and 0.92 ± 0.39 μg g⁻¹, respectively). No significant differences were measured between commercial and authenticated samples.     

Production, purification and thermal characterisation of invertase from a newly isolated Fusarium sp. under solid-state fermentation

Production of invertase employing a newly isolated Fusarium sp. under solid-state fermentation was optimised. Different process parameters were optimised. The maximum enzyme activity under optimum conditions was 47.23 ± 2.12 U gds⁻¹ with nitrogen additives. The enzyme was purified by ammonium sulphate precipitation, diethylaminoethyl cellulose ion-exchange chromatography and Sephadex gel filtration. This protocol gave 20.25-fold purification and 5.53% recovery. The optimum pH and temperature for activity were 5.0 and 50 °C. The K _m and V _max values for the enzyme were 8.33 m m and 21.48 μmol min⁻¹, respectively. A detailed kinetic study of thermal inactivation has been carried out. Enthalpy of activation (Δ H *) decreased when entropy (Δ S *) of activation increased at higher temperatures. Moreover, free energy of denaturation (Δ G *) increased at higher temperature making the enzyme thermally stable. A possible explanation for the thermal inactivation of invertase at higher temperatures is also discussed.     

Microwave heat treatment of leek: drying kinetic and effective moisture diffusivity

The effect of microwave drying technique on moisture ratio, drying time and effective moisture diffusivity of white and green parts of leek ( Allium porrum ) were investigated. By increasing the sample amount (100–300 g) at constant microwave output power of 180 W, the drying time increased from 52 to 130 min and increased from 55 to 135 min for white and green parts of leek, respectively. Effective moisture diffusivity values for white and green parts of leek ranged from 0.618 × 10⁻¹⁰ to 2.128 × 10⁻¹⁰ m².s⁻¹ and 0.256 × 10⁻¹⁰ to 0.611 × 10⁻¹⁰ m² s⁻¹, respectively. Among the models proposed, Midilli et al. model gave a better fit for all drying conditions applied. The activation energy for microwave drying of white and green parts of leek was calculated using an exponential expression based on Arrhenius equation; found as 0.9530 and 1.2045 W g⁻¹, respectively. The dependence of drying rate constant on effective moisture diffusivity gave a linear relationship.     

Selected polycyclic aromatic hydrocarbons in smoked tuna, swordfish and Atlantic salmon fillets

The presence of polycyclic aromatic hydrocarbons (PAHs) in commercial smoked fillets of tuna, swordfish and Atlantic salmon was studied. In Europe, the smoking technique is widely used in fish processing and these species are the most representative of the taste of consumers for smoked products. Samples were purchased on the Italian market and analysed by HPLC. Mean concentrations (ng g⁻¹) of acenaphthene (4.4, 6.2, 11.2), phenanthrene (11.5, 18.5, 8.9), anthracene (2.4, 5.2, 1.8), fluoranthene (17.0, 9.4, 4.7), benzo( k )fluoranthene (0.3, 0.1, 0.2) and benzo( a )pyrene (1.3, 0.1, 0.4) were found in Atlantic salmon, tuna and swordfish respectively. Benzo( b )fluoranthene (1.2 ng g⁻¹) was detected only in Atlantic salmon whereas dibenz( a,h )anthracene was never detected in this species, but only in tuna (0.5 ng g⁻¹) and swordfish (1.1 ng g⁻¹). Atlantic salmon contained the highest level of benzo( a )pyrene (2.8 ng g⁻¹) which is below the European regulatory level of 5 ng g⁻¹.     

Collagenous hydrolysates from untraditional sources of proteins

Synopsis Sufficiently pure collagenous hydrolysates, suitable for application in skin and hair care cosmetics, have been prepared through biotechnological methods with the use of commercially available enzymatic preparations from short cattle tendons (musculus extensor communis, musculus flexor digitorum, musculus flexor digitorum profundis). These hydrolysates contain neither lipoid nor aminosaccharide components, content of primary amino groups reaches around 1.1 mmol g⁻¹ and the average molecular weight of the resulting collagenous hydrolysates does not exceed 2000 g mol⁻¹ (2.0 kDa). Short cattle tendons represent a relatively pure and easily available source of collagens and are, despite their generally known low nutritional value, used only as a feeding mixture component.     

The effects of ice storage on inosine monophosphate, inosine, hypoxanthine, and biogenic amine formation in European catfish (Silurus glanis) fillets

European catfish fillets in ice were evaluated by measuring nucleotide components and biogenic amine contents and these then compared with sensory and microbiological assessment during the 21 days of iced storage. Analyses were carried out using two different rapid HPLC methods for nucleotid degradation products and biogenic amine contents in European catfish fillets. Sensory evaluation showed that storage life of European catfish found to be 14–18 days. Initial inosine monophosphate (IMP) level was 12.6 μmol g^­1 and then decreased during the rest of storage period. Inosine (INO) level increased rapidly until 7 days of storage. Hypoxanthine (Hx) level increased almost linearly with storage time. The most accumulated biogenic amines were putrescine, cadaverine, spermidine, spermine, and serotonin in all the European catfish fillets during the storage, although the formation of biogenic amines levels was fluctuated. Histamine was only detectable at 4 and 7 days of storage as low as 1 mg 100 g^­1 fish. Total viable count in European catfish increased rapidly with storage time and reached ≤10⁹ cfu g^­1 when the fillets were not acceptable for consumption.     

Microbiological quality of sous-vide cook chill fish cakes during chilled storage (3 °C)

Fish cakes prepared from emperorbream ( Lethrinus lethrinus ) were vacuum packed (VP), conventionally cook-chilled (CCC) and sous-vide cook-chilled (SVCC) and examined for their microbiological quality and safety during chilled storage (3 °C) for a period of 3, 5 and 16 weeks, respectively, in comparison with conventional pack(CP). The shelf life of CP, VP, CCC and SVCC packs of fish cakes were 2, 2, 4 and 16 weeks, respectively, based on the acceptable break point of the overall sensory scores. The total bacterial counts were 5 log cfu g⁻¹, in CP, VP and CCC packs; and 3 log cfug⁻¹ in SVCC pack on sixteenth week. Total lactic acid bacteria were 2 log cfu g⁻¹ on 2 and 3 weeks in CP and VP, respectively. Staphylococci were detected in all packs on sixteenth week at 2 log cfu g⁻¹. Total bacilli were detected in CP and VP at 3 log cfu g⁻¹ level after 2 weeks. Aeromonads were detected after 1, 2 and 4 weeks in CP, VP and CCC packs at 3 log cfu g⁻¹. Total anaerobic sulphite-reducing clostridia were detected only in CP and CCC packs at 3 MPN counts g⁻¹ level on the final day.     

Effects of meat piece size and phosphate on maximum slicing rate, cooking loss and sensory quality of a re-formed pigmeat shoulder product

Summary Two pre-tumbling treatment variables (meat piece size; raw product phosphate content) were evaluated for their effects on maximum slicing rate (MSR), cooking loss and sensory quality of a commercially produced, cooked re-formed pigmeat shoulder product. At 0.457% phosphate, incremental reductions in meat piece size which increased specific surface from 0.60 to 0.93 cm² cm⁻³ enabled MSR to increase from 300 to 400 slices min⁻¹, reduced cooking losses from 0.875 to 0.60% and gave a more tender product. At 0.60 cm² cm⁻³ specific surface, increasing phosphate incrementally from 0.457 to 0.532% produced similar positive effects on MSR and cooking loss but at phosphate above 0.482% sensory quality declined. Combination of optimal specific surface (0.93 cm² cm⁻³) and phosphate (0.482%) permitted a MSR of 420 slices min⁻¹, reduced cooking loss to 0.50% and gave an acceptable product. These process modifications can thus be advocated for improved production rate, yield and sensory quality.     

The level of polyaromatic hydrocarbons in kajal and surma of major Indian brands

Kajal and surma are eye cosmetics extensively used in Indian subcontinent. Kajal is prepared by burning of vegetable oil and butter oil while surma by grinding of the stones. High performance liquid chromatography and gas chromatography–mass spectrometry instruments were used for quantification and confirmation of 16 polyaromatic hydrocarbons (PAHs). Significant concentration of PAH was found in all the samples examined. The median concentration of PAH ranged from 0.14 (lowest, anthracene) to 31.18 μg g⁻¹ [dibenz(a,h)anthracene] in kajal sample and from not detectable concentration (naphthalene) to 197.47 μg g⁻¹ of benzo(a)pyrene in surma sample. Fifteen PAHs were detected in all the samples. Therefore the use of kajal and surma in eye should be strictly restricted.     

Influence of particle size fractions on the physicochemical properties of maize flour and textural characteristics of a maize-based nonfermented food gel

The physicochemical properties of fractionated maize flour and the textural characteristics of a maize-based nonfermented food gel (maize tuwo ) prepared from the respective fractionated flours were evaluated. The maize flour was fractionated into four fractions: <75 μm, 75–150 μm, 150–300 μm, 300–425 μm and whole meal (<425 μm). There were variations in the selected chemical constituents of fractionated maize flour including protein (2.9–4%), ash (0.80–0.97%), crude fibre (0.73–0.91%) and damaged starch (10.1–17.4%). The fractionated maize flour gave variable bulk density (0.80–0.93 g cm⁻³), water absorption capacity (1.9–2.1 g g⁻¹) and oil absorption capacity (1.7–2.1 g g⁻¹). The colour characteristics of the fractionated maize flour and the pasting properties were all affected by the fractionation. The cohesiveness index (strain at peak compressive force) of the food gel from the flour fractions ranged between 15% and 19.5% while the softness index of the food gel ranged between 16.7 and 17.5 mm. The relative high cohesiveness and softness indexes (i.e. 19.5% and 17.4 mm respectively) of maize tuwo prepared from the flour fraction of 75–150 μm can predispose the food gel towards easier hand-mouldability and swallowability respectively; being important quality indicators for its acceptability.     

J. Cosmet. Sci., 59, 441–448 (September/October 2008)Simultaneous determination of heavy metals in cosmetic products

An extremely small amount of several heavy metals have been detected in cosmetic products as impurities, which can cause skin allergies through percutaneous adsorption on the skin. We present here a fast, accurate, and highly sensitive method for simultaneous determination of Pb²⁺, Fe²⁺, Cu²⁺, Ni²⁺, Zn²⁺, Co²⁺, Cd²⁺ and Mn²⁺ in coloring agents and cosmetic products, to be evaluated by ion chromatography. All of these metals are well separated through a bifunctional ion-exchange column (IonPac CS5A) and detected by post-column reaction and spectrophotometric detection. The calibration graphs are linear ( r ² > 0.999), in the range 0.1–1000 μg ml^-1. Detection limits for a 200-μl sample solution are at the μg L^-1 level, which is sufficient for judging whether the product is safe or not. The relative standard deviations (RSDs) of the retention time and the peak area are less than 0.21 and 1.24%, respectively. The recovery rates are 97–104%. The result shows that the proposed determination method is more sensitive, more accurate, and faster than current methods such as HPLC, ICP-MS and Flame-AAS. The new method was applied to analyse the amount of heavy metals contained in 22 cosmetic products and 11 coloring agents.     

Radical scavenging and antimicrobial activity of horsetail (Equisetum arvense L.) extracts

A reversed-phase high performance liquid chromatography (RP-HPLC) separation on C₈ column and quantitative method were developed to analyse hydroxyl derivatives of benzoic and cinnamic acid and flavonoids in horsetail ( Equisetum arvense L.) extracts. Total phenolic content of n -butanol, ethyl acetate and water extracts, determined by the Folin-Ciocalteu method, was 96.4, 26.4 and 15.4 mg g⁻¹ of dry extracts, respectively. The antioxidative activity of horsetail extracts was tested by measuring their ability to scavenge stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) and reactive hydroxyl radicals by electron spin resonance spectroscopy. The results demonstrated that the free radical scavenging activity (versus both DPPH and hydroxyl radicals) depended on the type and concentration of applied extracts; the highest DPPH (EC₅₀ = 0.65 mg mL⁻¹) and hydroxyl radical scavenging activities (EC₅₀ = 0.74 mg mL⁻¹) were obtained in the case of n -butanol extract. The radical scavenging activity of extracts significantly correlated with total phenolic content. The antimicrobial tests showed that ethyl acetate and n -butanol extracts inhibited the growth of tested bacteria.     

Carotenoid composition and vitamin A value of some native Brazilian green leafy vegetables

The composition of carotenoids in five native Brazilian leafy vegetables was determined. The ranges of total carotenoid contents of Amaranthus viridis, Lepidium pseudodidymum, Xanthosoma spp., Sonchus oleraceus , and Portulaca oleracea were 347–468, 237–280, 225–361, 149–334 and 71–109 μg g⁻¹, with lutein and β-carotene predominating. The mean β-carotene contents (μg⁻¹) and vitamin A values (retinol equivalents RE_g⁻¹) were 110 and 18.4, 84.6 and 14.1, 67.3 and 11.2, 62.9 and 10.5, 29.8 and 4.99, respectively. The leaves contained 54–61% of lutein plus violaxanthin, 24–34% of β-carotene, 10–14% of neoxanthin and traces of zeaxanthin and α-crypto-xanthin. The native leafy vegetables were richer sources of provitamin A than the cultivated leafy vegetables analysed previously, justifying their commercial production.     

Analysis of isothiocyanates in newly generated vegetables, Baemuchae (×Brassicoraphanus) as affected by growth

Isothiocyanates in Brassica exhibit anticancer properties related to induction of phase II detoxification enzymes. Currently, variations of isothiocyanates was evaluated in Baemuchae (× Brassicoraphanus ), which was newly generated by inter-specific hybrid crops between radish ( Raphanus sativus L.) and Chinese cabbage ( Brassica campestris L. ssp. pekinensis ). A high-performance liquid chromatography system coupled with an evaporative light scattering detector and gas chromatography–mass spectrometry were utilised to identify and quantify isothiocyanates including sulforaphene and sulforaphane in prepared plants. Sulforaphene constituted a major isothiocyanate in Baemuchae and radish, while sulforaphane was detected in broccoli. Sulforaphane contents varied during broccoli growth, with a constant decrease noted from 144.9 ± 8.69 in sprouts to 8.1 ± 1.07 μg g⁻¹ in young leaves. Sulforaphene contents in Baemuchae and radish sprouts were 172.6 ± 11.23 and 131.3 ± 4.08 μg g⁻¹, respectively, and were rarely affected by plant growth. The result supported that newly generated crop Baemuchae had potential to be utilised as functional material because of presence of sulforaphene.     

Phenolic composition and antioxidant capacity of different heat-processed forms of sweetpotato cv. 'Beauregard'

Sweetpotato [ Ipomoea batatas (L.) Lam.] cv. 'Beauregard' roots were cooked using three different heat-processing techniques (baked in a conventional oven, baked in a microwave oven, and boiled). Total phenolic content, individual phenolic acids, and antioxidant capacity were determined using Folin-Denis assay, HPLC (high-performance liquid chromatography), and DPPH (1,1-diphenyl-2-picrylhydazyl) assay, respectively. The skin tissue (raw or processed) contained the highest concentration of total phenolics. All heat-processing methods resulted in a significant loss in total phenolic content and antioxidant capacity of the skin tissue. However, compared with the other processing methods, conventional oven baking resulted in greater losses in antioxidant capacity of skin tissue. Total phenolic content ranged from a low of 1.58 mg chlorogenic acid equivalent g⁻¹ dry tissue weight in boiled pith tissue to a high of 17.7 mg chlorogenic acid equivalent g⁻¹ dry tissue weight in raw skin tissue. The antioxidant capacity was highest in raw skin tissue (22.9 mg Trolox equivalent g⁻¹ dry tissue weight). Chlorogenic acid was the principal phenolic acid found in all sweetpotato tissues. Caffeic acid and three isomers of dicaffeoylquinic acid (diCQA) were also identified and quantified.     

Microbiological, chemical and sensory assessment of (I) whole ungutted, (II) whole gutted and (III) filleted tilapia (Oreochromis niloticus) during refrigerated storage

The effects of gutting and filleting on microbiological, chemical, and sensory properties of tilapia ( Oreochromis niloticus ) stored under refrigeration were studied. All the tilapia samples were analysed periodically for microbiological (APC), chemical (pH, total volatile basic nitrogen, 2-thiobarbituricacid, K -value), and sensory characteristics. Results indicated that sensory data were in good agreement with microbiological data (APC rejection limit of 10⁷ CFU g⁻¹) and K -value (rejection limit of 60%). Storage life of (I) whole ungutted, (II) whole gutted and (III) filleted tilapia stored under refrigeration (5 ± 1 °C) can be expected to be 12, 10, and 6 days, respectively.