Characterization of the Lipid Fraction in Lamb Meat: Comparison of Different Lipid Extraction Methods

The aim of this study was to evaluate the performance of four different extraction methods commonly used to quantify the intramuscular lipid content in meat: the Association of Analytical Chemists (AOAC) method (reference method) and methods based on the use of a solvent mixture with different polarities, such as chloroform–methanol described by Folch et al. (J Biol Chem 226:497, 1957) and Christie (1989) or hexane–isopropanol described by Hara and Radin (Anal Biochem 90:420, 1978). The following parameters were taken into account: lipid content; relative proportions of neutral and polar lipids; fatty acid composition of total, neutral, and polar lipid fractions; and phospholipid composition. The use of a combination of solvents with different polarities (Hara–Radin, Folch, and modified Folch methods) was more effective in extracting intramuscular lipids than the use of a single solvent (AOAC, reference method). The Hara–Radin method provided a cleaner lipid extract with a significantly higher content of total fatty acids than that obtained with the Folch and modified Folch methods. The lower polarity of the hexane–isopropanol mixture allowed us to obtain an extract richer in neutral lipids (triglycerides and diglycerides) and thus in saturated and monounsaturated fatty acids. The percentage distribution of individual fatty acids in the neutral lipid fraction was generally not affected by the extraction method adopted, while lipid obtained with both the Hara–Radin and Folch methods had a polar fraction with a higher percentage of polyunsaturated fatty acids. The use of the Hara–Radin method provided a polar fraction with less nonlipid material and lower phospholipid degradation.     

Modification of appetite by bread consumption: A systematic review of randomized controlled trials

The inclusion of different ingredients or the use of different baking technologies may modify the satiety response to bread, and aid in the control of food intake. The aim of this study was to perform a systematic search of randomized clinical trials on the effect of bread consumption on appetite ratings in humans. The search equation was (“Bread”[MeSH]) AND (“Satiation”[MeSH] OR “Satiety response”[MeSH]), and the filter “clinical trials.” As a result of this procedure, 37 publications were selected. The satiety response was considered as the primary outcome. The studies were classified as follows: breads differing in their flour composition, breads differing in ingredients other than flours, breads with added organic acids, or breads made using different baking technologies. In addition, we have revised the data related to the influence of bread on glycemic index, insulinemic index and postprandial gastrointestinal hormones responses. The inclusion of appropriate ingredients such as fiber, proteins, legumes, seaweeds and acids into breads and the use of specific technologies may result in the development of healthier breads that increase satiety and satiation, which may aid in the control of weight gain and benefit postprandial glycemia. However, more well-designed randomized control trials are required to reach final conclusions.     

Isolation and structure elucidation of phenolic compounds from Cyclopia subternata Vogel (honeybush) intact plant and in vitro cultures

In the presented work, an insight was made into the polyphenolic composition of intact plant material and in vitro cultures of indigenous South African plant Cyclopia subternata Vogel (honeybush). Ethyl acetate fractions of methanol extracts were separated by means of gravity column chromatography and/or semipreparative HPLC on two serially connected monolithic RP-18 columns. The structures of the isolated compounds were determined by means of 1D and 2D NMR techniques and additionally confirmed by LC-DAD-ESI-MS. Apart from the previously described honeybush components, that is mangiferin (1), scolymoside (2), hesperidin (3) and narirutin (4), three additional compounds: iriflophenone 3-C-β-glucoside (benzophenone) (5), phloretin 3′,5′-di-C-β-glucoside (dihydrochalcone) (6), and isorhoifolin (flavone) (7) were identified for the first time in the herb of C. subternata. Additionally, three isoflavone glucosides, namely calycosin 7-O-β-glucoside (8), rothindin (9) and ononin (10), which had not been previously reported in Cyclopia plants, were identified in the callus of the above species. As far as the authors are concerned, this is the first report on the presence of benzophenone and dihydrochalcone derivatives in Cyclopia genus.     

Identification and characterization of a chitinase of Stenotrophomonas maltophilia, a bacterium that is antagonistic towards fungal phytopathogens

A rhizosphere strain of Stenotrophomonas maltophilia strain MUJ that is strongly antagonistic towards fungal phytopathogens secretes to the culture medium a single form of active chitinolytic enzyme belonging to family 18 of glycosyl hydrolases. The chitinase was purified by a two-stage procedure embracing fractionation with ammonium sulfate and affinity chromatography. The molecular mass of the purified enzyme determined by SDS-PAGE was approximately 52 kDa. The enzyme demonstrated highest activity at 45°C and pH 6.8. The enzymatic protein showed considerable thermal stability during 2 h incubation at 45°C. The activity of the enzyme was strongly inhibited in the presence of Hg²⁺ and Cu²⁺. By applying mass spectrometry analysis, the peptides derived from the purified chitinase were assigned to amino acid sequences of the type ChiA chitinases synthesized by Stenotrophomonas bacteria. The purified enzyme inhibited the growth of fungal phytopathogens belonging to the genera Fusarium, Rhizoctonia and Alternaria.     

Rapid virus detection procedure for molecular tracing of shellfish associated with disease outbreaks

Detection of pathogenic viruses in oysters implicated in gastroenteritis outbreaks is often hampered by time-consuming, specialist virus extraction methods. Five virus RNA extraction methods were evaluated with respect to performance characteristics and sensitivity on artificially contaminated oyster digestive glands. The two most promising procedures were further evaluated on bioaccumulated and naturally contaminated oysters. The most efficient method was used to trace the source in an outbreak situation. Out of five RNA extraction protocols, PEG precipitation and the RNeasy Kit performed best with norovirus genogroup III-spiked digestive glands. Analyzing 24-h bioaccumulated oysters revealed a slightly better sensitivity with PEG precipitation, but the RNeasy Kit was less prone to concentrate inhibitors. The latter procedure demonstrated the presence of human noroviruses in naturally contaminated oysters and oysters implicated in an outbreak. In this outbreak, in four out of nine individually analyzed digestive glands, norovirus was detected. In one of the oysters and in one of the fecal samples of the clinical cases, identical norovirus strains were detected. A standard and rapid virus extraction method using the RNeasy Kit appeared to be most useful in tracing shellfish as the source in gastroenteritis outbreaks, and to be able to make effective and timely risk management decisions.     

Fat globule membranes in ewes' milk: The main enzyme activities during lactation

A trial was carried out on seven Massese ewes, from which individual milk samples were taken during lactation. All the enzyme activities investigated (oxidase activity of xanthine oxidoreductase, gamma-glutamyltranspeptidase, alkaline phosphatase and 5′-nucleotidase) were affected by the lactation phase, with the exception of the dehydrogenase activity of xanthine oxidoreductase (XOR). A higher oxidase activity (XO) of XOR was found when the diameter of milk fat globules was smaller. In addition, the absence of XO in colostrum led to the hypothesis that its antibacterial role is independent of its activity. The increase in alkaline phosphatase activity during lactation requires further research to better define the criteria for pasteurised sheep milk.     

Anti-inflammatory activity of American yam Dioscorea trifida L.f. in food allergy induced by ovalbumin in mice

Tropical ecosystems are particularly rich in edible plant species with different bioactive substances. Among the plants with promising benefits for health are species from the genus Dioscorea (Dioscoreaceae), especially those named yam. Recent studies have shown the beneficial effects of different species of Dioscorea, and its main constituent, diosgenine, in the treatment of food allergy. In this study we evaluated the potential of D. trifida, the only yam native from South America, in the treatment of ovalbumin (OVA) induced food allergy in Balb/c mice. HPLC/DAD analysis showed the presence of three very distinctive groups of natural products in extracts and fractions: (I) very polar substances, including allantoin, (II) phenolic substances as flavonoids and phenolic acids and (III) diosgenin and derivatives. Sensitive mice received casein feed with supplementation of crude extract (CE) and fractions. The supplementation with all products from D. trifida reduced IGE, intestinal oedema and mucus production, parameters observed in OVA allergic mice. The results showed the potential of this food to prevent or treat this disease and the necessity to be better explored.     

Phenols,Flavonoids, and Antioxidant and Antibacterial Activity of Leaves and Stem Bark of Morus Species

Leaves and stem bark composition from Morus species (M. alba var. alba, M. alba var. rosa and M. rubra) was evaluated for its antioxidant and antimicrobial activities in order to enhance its therapeutic uses. Total phenolics and flavonoids contents were estimated in hydromethanolic and aqueous extracts. Results showed highest content in M. rubra leaves aqueous extract (1129 mg gallic acid equivalent/100 g dry weight and 816 mg gallic acid equivalent/100 g dry weight, respectively). Using 2,2-diphenyl-1-picrylhydrazyl assay, the highest antioxidant activity was obtained in aqueous stem barks extracts. M. alba var. alba has an IC₅₀ of 2.84 mg/ml and the IC₅₀ value of M. rubra was the highest (4.78 mg/ml). ABTS^.+ (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)) method and reducing power assay were used to confirm the results from the 2,2-diphenyl-1-picrylhydrazyl test. All extracts expressed considerable free radical-scavenging properties. Hydromethanolic and aqueous extracts were tested against Staphylococcus aureus, Enterococcus feacalis, Staphylococcus epidermis, Escherichia coli, and Salmonella Typhimurium bacteria. Hydromethanolic stem bark extracts have the highest antimicrobial activities, and it may be a good antimicrobial agent for human gastrointestinal infections. This plant could be used as an additive to foods and also as a possible source to obtain new and effective herbal medicines to treat infections of multi-drug resistant strains of microorganisms.     

Modelling the survival of Enterobacter cloacae in a model olive cover brine solution

The main goal of this research was the evaluation of the survival of Enterobacter cloacae in a model olive brine. Two different assays were run; the first experiment assessed the viability of the target in brines containing NaCl (6–12%) and p‐coumaric acid (0.0–0.05%), adjusted to different pHs (4–10) and stored at 10–30 °C for 9 days. The death rate and cell levels at selected times were modelled with a polynomial equation to highlight the individual and interactive effects of NaCl/p‐coumaric acid/pH/temperature. Then, a second experiment was run for 3 months (temperature, 10 °C; pH, 4.5–5.5; NaCl, 6–8%). The survival of E. cloacae was affected mainly by pH, then by salt and temperature; however, the significance of the variables changed within the time, as salt and temperature acted in a significant way only after 1 day.     

Efficacy of different chemicals on shelf life extension of parsley stored at two temperatures

Four different chemical treatments, GA₃, 1‐MCP, essential oils and nano‐Cu, were applied immediately after harvest to Petroselinum crispum (Mill) plants. The efficacy of the above chemicals on shelf life extension of parsley stored at 5 °C and 20 °C was determined by analysing physiological and biochemical factors that determine quality standards of storage fresh parsley. Nonsprayed parsley revealed the highest loss of weight, ascorbic acid, pigments and an enhancement of CO₂ production and lipid peroxidation at 5 °C and 20 °C of storage. Nano‐Cu was more effective for delaying weight loss and revealed a better storage capacity. GA₃, 1‐MCP and essential oils sprays were more effective in ascorbic acid retention at 20 °C than at 5 °C, whereas all substances protect samples from lipid peroxidation. Essential oils were more clearly inhibitory towards both total viable counts and yeast infection. Our results suggest that GA₃, 1‐MCP, essential oils and Nano‐Cu exert their function through different mechanisms during ripening and could provide an effective and complementary means for maintaining high‐quality parsley leaves after harvest.