Evaluation of flavonoid and polyphenol constituents in mulberry leaves using HPLC fingerprint analysis

The mulberry leaf is a promising dietary source of antioxidants due to its high levels of beneficial compounds. To further examine its antioxidant properties, twelve batches of authenticated mulberry leaf, with total flavonoid contents (TFC) ranging from 24.34 mg g⁻¹ DW to 58.42 mg g⁻¹ DW and total polyphenol content (TPC) ranging from 11.49 mg g⁻¹ DW to 30.03 mg g⁻¹ DW, were investigated. According to Spearman’s coefficient, antioxidant activities, including the DPPH radical scavenging assay and the ferric reducing antioxidant power (FRAP), were positively correlated with TFC and TPC. The HPLC-DAD analysis results identified the characteristic fingerprint peaks in mulberry leaves as chlorogenic acid, rutin, quercetin 3-O-glucoside and kaempferol 3-O-glucoside, all of which directly contribute to the antioxidant capacity of mulberry leaves. Notably, young mulberry leaves showed higher antioxidant capacity than those of mature leaves. These promising results help create a compelling case for future development of mulberry leaf products.     

Environmental factors affect efficacy of some essential oils and resveratrol to control growth and ochratoxin A production by Penicillium verrucosum and Aspergillus westerdijkiae on wheat grain

This study determined the efficacy of three essential oils (bay, clove and cinnamon oil) and the antioxidant resveratrol (0–500 μg g⁻¹) on the control of growth and ochratoxin A (OTA) production by Penicillium verrucosum and Aspergillus westerdijkiae (=A. ochraceus) under different water activity (a_w, 0.90, 0.95, 0.995), and temperature (15, 25 °C) conditions on irradiated wheat grain. The most effective treatment (resveratrol) was then tested on natural grain. The ED₅₀ values for growth inhibition by the oils were 200–300 μg g⁻¹ at the a_w and the temperatures tested. For resveratrol, this varied from <50 μg g⁻¹ at 0.90–0.95 a_w to >350 at 0.995a_w at both temperatures. The ED₅₀ values for the control of OTA were slightly lower than for control of growth, with approx. 200 μg g⁻¹ required for the oils and 50–100 μg g⁻¹ of the antioxidant, at 0.90/0.95a_w and both temperatures. In wet grain (0.995a_w), higher concentrations were required. For growth there were statistically significant effects of single-, two- and three-way interactions between treatments except for concentration×temperature and concentration×temperature×essential oil/antioxidant treatment. For OTA control, statistically significant treatments were a_w, temperature×a_w, concentration×temperature, treatment×concentration, and three-way interaction of concentration×a_w×treatment for P. verrucosum and A. westerdijkiae. Subsequent studies were done with the best treatment (resveratrol, 200 μg g⁻¹) on natural wheat grain with either P. verrucosum or A. westerdijkiae at 0.85–0.995a_w and 15/25 °C over 28 days storage. This showed that the populations of the mycotoxigenic species and OTA contamination could be reduced by >60% by this treatment at the end of the storage period.     

Extraction and determination of ellagic acid contentin chestnut bark and fruit

Chestnuts are an important economic resource in the chestnut growing regions, not only for the fruit, but also for the wood. The content of ellagic acid (EA), a naturally occurring inhibitor of carcinogenesis, was determined in chestnut fruits and bark. EA was extracted with methanol and free ellagic acid was determined by HPLC with UV detection, both in the crude extract and after hydrolysis. The concentration of EA was generally increased after hydrolysis due to the presence of ellagitannins in the crude extract. The concentration varied between 0.71 and 21.6 mg g⁻¹ (d.w.) in un-hydrolyzed samples, and between 2.83 and 18.4 mg g⁻¹ (d.w.) in hydrolyzed samples. In chestnut fruits, traces of EA were present in the seed, with higher concentrations in the pellicle and pericarp. However, all fruit tissues had lower concentrations of EA than had the bark. The concentration of EA in the hydrolyzed samples showed a non-linear correlation with the concentration in the unhydrolyzed extracts.     

Composition,characterisation and analysis of seed oil of Suaeda salsa L

Awareness of vegetable oils being beneficial for health has attracted researchers in exploring different vegetable oils. In this study, Suaeda salsa L. seed oil was extracted and characterised. The yield of S. salsa L. seed oil was 25.99%. Acidity, iodine number, saponification number, peroxide value and unsaponifiable matter were used to assess seed oil quality. Melting point and melting enthalpy were found to be ?35.75 °C and 26.39 J g^?1, respectively, from differential scanning calorimeter‐melting curves. Fatty acid and triacylglycerol composition of this oil was analysed by GC‐MS and HPLC‐MS, respectively. The main fatty acid in S. salsa L. seed oil is Linoleic (65.03%), and the dominant triacylglycerols (TAGs) were LLL and OLL. The oil was found to have high amounts of α‐tocopherol (36.72 mg 100 g^?1) and β‐tocopherol (34.76 mg 100 g^?1). All the results suggest that S. salsa L. seed oil may have potential applications in relating industries.     

Inulin and probiotic concentration effects on fatty and linoleic conjugated acids in cream cheeses

The aim of this study was to evaluate the changes in the lipid profile, especially in conjugated linoleic acid (CLA), in 12 cream cheese batches with different prebiotic (inulin) and probiotic (Bifidobacterium animalis and Lactobacillus acidophilus) concentrations stored for 45 days at 8 ± 0.5 °C and analyzed every 15 days. A Central Rotational Composite Design was used to establish the prebiotic and probiotic concentrations. The effect of the pre- and probiotic concentrations on CLA contents (mg g⁻¹ of fat) was verified by plotting the response surface. The linear, quadratic, and interaction coefficients of the multiple linear regression for both prebiotic and probiotics were not significant (p > 0.05). No significant changes were observed neither in the lipid profile nor in the CLA content among the different batches, in which fatty acid composition and CLA concentrations were similar to the milk used in the preparation of the cream cheese and also to the control batch.     

Control of food spoiling bacteria in cooked meat products with nisin,lacticin 3147, and a lacticin 3147-producing starter culture

Nisin, in the form of the commercial product Nisaplin, and lacticin 3147 in whey powdered form were added to minced pork-meat in amounts of 0.15% (w/w) and 1.5% (w/w), respectively. The meat was cooked and inoculated with a Staphylococcus aureus strain of meat origin and a Listeria innocua strain at a level of 10⁷ or 10⁵ CFU g^–1. The batches were stored vacuum-packaged for 21 days at 8 °C. Nisin and lacticin 3147 immediately reduced the L. innocua population at the time of inoculation. Nisin showed higher inhibitory activity than lacticin 3147. During the storage period, a slight L. innocua growth was observed in the batches inoculated with the larger inoculum, and a bacteriostatic effect was observed against Listeria in the batches inoculated with 10⁵ CFU g^–1. Nisin maintained a constant S. aureus population in the cooked batch inoculated with 10⁷ CFU g^–1, although the bacteriocin was capable of reducing the amount of S. aureus by 90% in the batch inoculated with 10⁵ CFU g^–1. On the other hand, lacticin 3147 did not show an inhibitory effect against S. aureus in the cooked meat. The starter culture Lactococcus lactis DPC 303-T4 (containing the conjugative plasmid encoding production of lacticin 3147) was inoculated in a portion of a Longissimus dorsi pork muscle with brine. L. lactis DPC 303-T4 performed a good fermentation, but lacticin 3147 production was not found after 7 days at 12 °C of storage.     

Uneven application can influence the efficacy of s-methoprene against Rhyzopertha dominica (F.) in wheat

The Juvenile Hormone analogue s-methoprene is used to protect stored grain from pests such as the lesser grain borer, Rhyzopertha dominica (F.). The possibility that uneven application influences s-methoprene efficacy against this species was investigated in the laboratory. Adults of methoprene-susceptible strains were exposed for 14 days to wheat treated at doses of up to 0.6 mg kg⁻¹, or to mixtures of treated and untreated wheat giving equivalent average doses. Adult mortality after exposure to treated wheat was negligible in all cases (≤3.3%) and there was no significant effect of either average dose or evenness of application. In contrast, the number of adult progeny depended on both the average dose and evenness of application. Average doses of 0.3 and 0.6 mg kg⁻¹ reduced the number of live F₁ adults by 99–100% relative to the untreated wheat and no effect of evenness of application was detected. At lower doses, however, efficacy tended to decrease with increasing unevenness of application. When adults from the parental generation were transferred to untreated wheat for another 14 days neither the average dose nor evenness of application in the wheat from which they came had any significant effect on reproduction of these adults. This study demonstrates that uneven application can reduce the efficacy of s-methoprene against R. dominica, but that this is unlikely to influence the performance of s-methoprene against susceptible populations at target doses likely to be used in practice (e.g. 0.6 mg kg⁻¹ in Australia). However, the possibility that uneven application leads to underdosing and selects for resistance should be investigated.     

The effects of temperature and pH on the extraction of oxalate and pectin from green kiwifruit (Actinidia deliciosa L.), golden kiwifruit (Actinidia chinensis L.), kiwiberry (Actinidia arguta) and persimmon (Diospyros kaki)

Oxalates and pectin were extracted from four locally grown fruits at three different pH levels, 6.9, 0.6 and ?0.3, at two different temperatures, 21 and 80 °C. Green kiwifruit (Actinidia deliciosa L. Hayward), golden kiwifruit (Actinidia chinensis L. Hort 16A Zespri), kiwiberry (Actinidia arguta, CV. Takaka Green) and persimmon (Diospyros kaki) contained moderate levels of oxalates. Total and soluble oxalates were more efficiently extracted at 21 °C using 2 m HCL, while the highest amounts of pectin were extracted from the fruits at 80 °C using 0.2 m HCL. Extraction using 0.2 and 2 m HCL gave the highest yields of total oxalates, which ranged from 47.1 to 220.4 mg total oxalates per 100 g dry matter (DM) for persimmon and kiwiberry, respectively. Extraction using water at 21 °C gave soluble oxalate contents ranging from 21.2 mg 100 g^?1 DM, for persimmon, to 105.0 mg 100^?1 DM, for kiwiberry fruits. Extraction of pectin was not achieved efficiently using water at either temperature, while extraction using 2 m HCL gave lower values; optimal extractions of pectin were achieved at 80 °C using 0.2 m HCL.     

Microbiological quality of the fish species Trachurus murphyi, sold at the retail level in the town of Valdivia, Chile

A microbiological survey of 80 fish samples from the species Trachurus murphyi (common name ‘jurel’), sold at retail level in the town of Valdivia, Chile, was conducted. The aerobic plate count mean (geometric) was 1·91 × 10⁶ g⁻¹ with a range from 3·90 × 10⁴ g⁻¹ to 3·12 × 10⁸ g⁻¹. The average (geometric) coliform Most Probable Number (M.P.N.) was 411 g⁻¹ with a range from 15 g⁻¹ to over 1100 g⁻¹, while the fecal coliform M.P.N. showed an average (geometric) of 5·3 g⁻¹ with counts ranging between 3·6 g⁻¹ and more than 1100 g⁻¹. Bacteria from the genus Salmonella were not found in any of the samples tested.The average pH value of the fish meat was 6·29 fluctuating between 5·87 and 7·03. Taking as a basis the microbiological standards given for frozen fish, a high percentage of the samples did not meet with the requirements set by the Chilean Sanitary Food Regulations.     

Comparison of nutritional value and microbiological status of new imported fish species on the German market

Proximate composition, fatty acid profile, other nutritional values and spoilage indicators were examined in the muscle meat of five species: barramundi (Lates calcarifer) from various origins, tilapia (Oreochromis spp.) of different qualities, cobia (Rachycentron canadum) and leather jacket (Aluterus monoceros) from the Pacific Ocean and Patagonian grenadier (Macruronus magellanicus) from South America. Lowest lipid contents (0.4% and 0.8%) were found in leather jacket and cobia. Leather jacket fillets had lowest protein (16.2%) and highest sodium chloride content (4.9%). Concentrations of ∑EPA + DHA were 0.1 g 100 g^?1 for tilapia and leather jacket, 0.2 g 100 g^?1 for barramundi and cobia and 0.7 g 100 g^?1 for Patagonian grenadier. Barramundi and tilapia were characterised by high taurine content (215 and 276 mg 100 g^?1 ww.), and cobia had only low levels (41 mg 100 g^?1 ww.). Iodine contents were low and selenium levels varied between 303 and 570 μg kg^?1 ww. No sign of spoilage was detected.     

Cashew nut oil: effect of kernel grade and a microwave preheating extraction step on chemical composition,oxidative stability and bioactivity

The cashew nut kernels can be broadly classified by colour, size, quality and integrity, into whole (W), butts (B), splits (S) and P (pieces). This work evaluated seven sizes and qualities of cashew kernel (B1, S1, W4, SP1, SP2, P2 and W240), for oil extraction. Then, two oil extraction methods, using cold pressing (CP) and microwave preheating (MP), respectively, were investigated. In evaluation of cashew kernel grades, the fat content varied between 51.6 and 57.6 g 100 g^?1, and the acidity and peroxide were low, indicating good chemical quality for all grades. The oil extracted by MP showed a higher induction time in the Rancimat test (46.25 h). The cashew nut oil showed bioactivity, mainly associated with the level of total phenolic compounds (CP: 202.17 mg 100 g^?1; MP: 371.95 mg 100 g^?1), and showed antiproliferative activity against cancer cells (lung, breast and liver) but only at high concentrations. The MP extraction preserved many components and increased the phenolic compounds in the cashew kernel oil, without promoting negative changes in its physicochemical and oxidative qualities.     

Determination and Evaluation of the Mineral Composition of Chinese Cabbage (Beta vulgaris)

Inductively coupled plasma optical emission spectrometry was used to determine the elements present in Chinese cabbage (Beta vulgaris). The accuracy of the method was confirmed by analysis of a certified reference material of spinach leaves. The study involved 57 samples that were collected in 13 Brazilian cities. Average concentrations of elements found per gram of Chinese cabbage were as follows: 3.44 mg g⁻¹ sodium, 5.09 mg g⁻¹ potassium, 1.25 mg g⁻¹ phosphorous, 0.85 mg g⁻¹ calcium, 0.49 mg g⁻¹ magnesium, 2.79 μg g⁻¹ manganese, 9.50 μg g⁻¹ iron, 0.74 μg g⁻¹ copper, 14.28 μg g⁻¹ zinc, and 6.44 μg g⁻¹ strontium. Principal component analysis and hierarchical cluster analysis demonstrated that there is no systematic difference in the mineral composition between the cabbage samples that were analyzed.     

Optimised condition for preparing sea cucumber ovum hydrolysate–calcium complex and its structural analysis

This study aimed to determine optimum preparation conditions of sea cucumber ovum hydrolysates–calcium (SCOHs–Ca) complexes by Box–Behnken design and further elucidate their microstructure characteristics using Fourier transform infrared spectroscopy, scanning electron microscope, atomic force microscopy and dynamic light scattering. The predicted calcium‐chelating capacity under the optimum conditions of the process variables was very close to the experimental value (53.45 ± 0.29 mg g^?1) determined in the batch experiment. Results demonstrated that the calcium bind to the SCOHs to form the SCOHs–Ca complexes primarily via interactions with carboxyl oxygen and amino nitrogen atoms. The prepared SCOHs–Ca complexes formed compact nanoparticles and exhibited a fold and porous network structure. These changes could be attributed to the interaction between peptides and calcium ions. Our findings provide a theoretical basis for the development of new calcium preparations as well as the high‐value utilisation of sea cucumber by‐products.     

Determination of the hormonal growth promoter 17α-methyltestosterone in food-producing animals: Bovine hair analysis by HPLC–MS/MS

This paper describes the development, validation and application of a confirmatory method to detect 17α-methyltestosterone (MT) in bovine hair, to aid in controlling the administration of this growth promoter in meat-producing animals. After cryogenic grinding, MT was removed from the hair matrix using a single step extraction procedure with acetonitrile. Hydroxylamine derivatisation was used to enhance analyte determination with an electrospray ionisation (ESI) source. Determination was carried out using a triple quadrupole liquid chromatography tandem mass spectrometer (LC–MS/MS) in multiple reaction monitoring mode (MRM). The method was validated in accordance with the criteria defined in Commission Decision 2002/657/EC and using deuterated testosterone (T-d₃) as the internal standard. The decision limit (CCα) was 0.07 ng g⁻¹ and the detection capability (CCβ) was 0.12 ng g⁻¹. Repeatability was CV% (7%), within-laboratory reproducibility was CV% (11.0%), and trueness was (87%). Applicability of the method was demonstrated in an animal study. Samples obtained from animal experiments were analyzed and the presence of MT was confirmed.     

Assessment of thermo‐oxidative rancidity in sunflower oil and fried potato chips stabilised with oleoresin sage (Salvia officinalis L.) and ascorbyl palmitate by altered triglycerides and electronic nose

Oleoresin sage (Salvia officinalis) (SAG) (200–1500 mg kg^?1), ascorbyl palmitate (AP) (100–300 mg kg^?1) and TBHQ (200 mg kg^?1) were assessed for delaying the thermo‐oxidation in sunflower oil (SO) during 18 h of frying (180 °C). Electronic nose compared the global aroma fingerprints of potato chips fried in oils. The chemical rancidity indices viz., fatty acids, total polar compounds (TPC), altered triglycerides (dimers, polymers, oxidised monomers, diglycerides), free fatty acids, conjugated dienes and induction periods were monitored along with physical indices viz., viscosity and colour. SO_SAG+AP (1309.62 + 270.71 mg kg^?1) outperformed SO_TBHQ by preserving polyunsaturated fatty acids (60.48% vs. 56.23%), retarding TPCs (28.16% vs. 29.91%), triglyceride dimers (90.24 vs. 95.82 mg g^?1) and polymers (25.40 vs. 26.98 mg g^?1) concomitantly extending the oil disposal time (basis 25% TPC) (15.9 vs. 14.7 h). The postfrying viscosity, colour values and global aroma fingerprints of fried chips indicate a close match between SO_SAG+AP and SO_TBHQ.     

Assessment of the microbiological safety of salad vegetables and sauces from kebab take-away restaurants in the United Kingdom

The purpose of this study was to establish the microbiological safety of salad vegetables and sauces served in kebab take-away restaurants. Comparison with published microbiological guidelines revealed that 4.7% of 1213 salad vegetable samples were of unsatisfactory microbiological quality due to Escherichia coli and/or Staphylococcus aureus levels at ≥10² cfu g⁻¹. Another 0.3% of salad samples were of unacceptable quality due to S. aureus at ≥10⁴ cfu g⁻¹ (2 samples) or the presence of Salmonella Kentucky (1 sample). Cucumber was the most contaminated salad vegetable with regards to unsatisfactory levels of E. coli (6.0%) or S. aureus (4.5%). Five percent of 1208 sauce samples were of unsatisfactory microbiological quality due to E. coli, S. aureus at ≥10² cfu g⁻¹ and/or Bacillus cereus and other Bacillus spp. at ≥10⁴ cfu g⁻¹. A further 0.6% of sauce samples were of unacceptable quality due to Bacillus spp. (Bacillus subtilis, Bacillus pumilus, Bacillus licheniformis) at ≥10⁵ cfu g⁻¹ or the presence of Salmonella Agbeni (1 sample). More samples of chilli sauce (8.7%) were of unsatisfactory or unacceptable microbiological quality than any other sauce types. The results emphasize the need for good hygiene practices in kebab take-away restaurants handling these types of ready-to-eat products.     

Antioxidant potential of extracts from peels and stems of yellow-fleshed and white cassava varieties

This study focused on the exploration of the potentials of extracting antioxidants from peels and stems of yellow-fleshed and white cassava varieties. The effect of particle size (0.2 and 0.5 mm) and variety on the phenolic content and antioxidant activity was assessed. The peels of the yellow-fleshed cassava variety with a particle size of 0.2 mm showed the highest phenolic content with 681.5 GAE mg 100 g⁻¹ and antioxidant activity of 19% and 425 μM TE g⁻¹ dry matter using DPPH and FRAP assays respectively. The stems of the white cassava with a particle size of 0.2 mm exhibited high phenolic content (442.4 GAE mg 100 g⁻¹) and antioxidant activity of 12.8% and 234 μM TE g⁻¹, better than the stem of the yellow-fleshed cassava. These results indicate that phenolic and antioxidant extractions were influenced by variety, the plant parts and particle size for the antioxidant assays.     

Effect of drying kinetics on main bioactive compounds and antioxidant activity of acerola (Malpighia emarginata D.C.) residue

This study investigates the drying kinetics of residue of acerola, in a fixed‐bed dryer, analysing the effect of the process variables on the antioxidant properties of the residue. A complete factorial design 3² has been performed, where the independent variables studied were as follows: air velocity (0.5, 1.0 and 1.5 m s^?1) and air‐drying temperature (40, 50 and 60 °C). The bioactive compounds studied were L‐ascorbic acid, total phenolic, total flavonoids and antioxidant activity (expressed as IC₅₀) was determined using free radical DPPH^?. Both independent variables studied have shown to be statistically significant. The content of ascorbic acid was the highest at 60 °C and 1.0 m s^?1 (126.2 ± 0.004 mg 100 g^?1) while for the fresh residue 16.12 ± 0.003 mg 100 g^?1, whereas the total phenolic showed the highest content at 50 °C and 1.5 m s^?1 (46.2 ± 0.003 mg gallic acid.100 g^?1) while for the fresh residue 12.59 ± 0.001 mg gallic acid.100 g^?1. The drying conditions play an important role in determining the final quality of the product mainly in terms of antioxidant activity.     

Effect of fermentation by Bacillus subtilis on antioxidant and cytotoxic activities of black rice bran

Black rice bran was fermented with Bacillus subtilis KU3 isolated from Korean traditional food, Kimchi. Antioxidant and cytotoxic activities of the fermented black rice bran were investigated. Total phenolic and anthocyanin contents decreased from 171.54 mg GAE g^?1 and 2.31 mg g^?1 to 139.13 mg GAE g^?1 and 2.12 mg g^?1, respectively, after fermentation. Antioxidant activities determined by 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) radical scavenging, β‐carotene bleaching and ferric thiocyanate assay were correlated with total phenolic and anthocyanin contents. Non‐fermented black rice bran extract (NFBE) showed greater antioxidant activities than fermented black rice bran extract (FBE). Cytotoxic activities measured by MTT assay showed that both NFBE and FBE had over 50% activities. The cytotoxic activities of FBE against MCF‐7 and HeLa cells were 71.65% and 68.07%, respectively, at 8.0 mg mL^?1, but those of NFBE were lower than 50%. These results suggested that the cytotoxic activity of black rice bran improved through fermentation, while antioxidant activity reduced.     

Lactose,glucose and galactose content in milk,fermented milk and lactose-free milk products

Lactose, glucose and galactose contents in milk and fermented milk products and their lactose-free alternatives, were determined. Storage of products up to the best-before dates had no effect on carbohydrate composition. Total galactose content in yoghurt, i.e., free galactose plus the galactose moiety of lactose, was 2.3–2.4 g 100 g⁻¹ (94–95% of that in milk), whereas that in Swedish soured milk and kefir was 1.9–2.0 g 100 g⁻¹ (75–79% of that in milk). Lactose levels in lactose-free milk and fermented milk products were below or close to detection limits for all products. Only small differences in total galactose content existed for the lactose-free alternatives of milk, yoghurt and filmjölk, all with average total galactose contents of 1.3–1.4 g 100 g⁻¹ (55–60% of that in milk). In contrast, lactose-free kefir had the same galactose content as milk, 2.4 g 100 g⁻¹.