Maria Fiorenza Caboni

Quality and standardisation of Royal Jelly

Departamento de Alimentos e Nutricao Experimental, Faculdade de Ciencias Farmaceuticas da Universidade de Sao Paulo (USP), Sao Paulo, Brazil. Received 26 June 2008, accepted subject to revision 18 August 2008, accepted for publication November 2008. *Corresponding author: Email: annagloria.sabatini@entecra.it

Development of a rapid method to determine phenolic and other polar compounds in walnut by capillary electrophoresis-electrospray ionization time-of-flight mass spectrometry.

The aim of this work was to develop a capillary electrophoresis-mass spectrometry (CE-MS) method to identify and quantify phenolic and other related polar compounds in walnut samples. The extraction capacity of several solvent mixtures of phenolic compounds from walnut by conventional solid-liquid extractions was tested, and CE and electrospray ionization MS parameters were optimized. The finalized procedure is able to determine many well-known phenolic compounds present in walnuts and provide relevant information about the presence of minor polar compounds. A new compound in walnut ((2E,4E)-8-hydroxy-2,7-dimethyl-2,4-decadiene-1,10-dioic acid 6-O-beta-d-glucopiranosyl ester, [M-H](-) 403.161m/z) with a structure similar to glansreginins was also identified. Phenolic compounds correspond to 14-28% of total polar compounds quantified. Aglycone and glycosylated ellagic acid represent the principal components and account for 64-75% of total phenols in walnuts. However, the sum of glansreginins A, B and (2E,4E)-8-hydroxy-2,7-dimethyl-2,4-decadiene-1,10-dioic acid 6-O-beta-d-glucopiranosyl ester was in the range of 72-86% of total quantified compounds. In addition, this is the first time that separation by CE with detection by electrospray ionization time-of-flight MS has been applied to the analysis of phenolic and other polar compounds in walnut samples, providing results in less than 15min.

Development of Functional Spaghetti Enriched with Long Chain Omega-3 Fatty Acids

ABSTRACT Results concerning the production of spaghetti enriched in long chain (LC) n-3 polyunsaturated fatty acids (PUFA) and, in particular, eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA) are reported. Pasta enrichment was obtained by adding different amounts of integrator (0.6, 1.2, and 1.8%) containing EPA (C20:5 n-3) and DHA (C22:6 n-3) in a microencapsulated form to commercial semolina. The addition of 1.2% integrator yielded spaghetti that provides ≈20% of the recommended daily intake of LC n-3 PUFA with high sensorial acceptability and low loss of LC n-3 PUFA after cooking (<10%). Thus, spaghetti fortified with EPA+DHA could be used to increase consumption of LC n-3 PUFA and to decrease the dietary n-6/n-3 ratio.

Evaluation of cholesterol and lipid oxidation in raw and cooked minced beef stored under oxygen-enriched atmosphere

Oxygen-enriched modified atmosphere packaging (MAP) represents an important means to stabilize meat colour but may lead to an increase in lipid oxidation, influencing the acceptability and safety of the product. In this work, the effect on cholesterol and lipid susceptibility to oxidation was investigated in commercial minced beef held under MAP (80% O(2)/20% CO(2)). Cholesterol oxidation products (COPs), peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) were determined, before and after pan frying, at 1, 8 and 15 days since packaging under refrigerated storage (3-4°C). 7α-Hydroxycholesterol, 7β-hydroxycholesterol and 7-ketocholesterol were the more abundant COPs identified. COPs significantly increased in raw beef during storage: after 1, 8 and 15 days since packaging COPs were at the levels of 10.4, 30.7 and 60.5μg/g of fat, respectively. Cooking did not affect cholesterol oxidation in freshly packaged minced beef but led to a rise in COPs amount with respect to raw muscle after 8 and 15 days of storage. The trend in cholesterol oxidation reflected the progressive increase in lipid peroxidation rate brought by MAP conditions.

Characterization of total, free and esterified phytosterols in tetraploid and hexaploid wheats.

Dietary plant sterols have received increasing attention in recent years due to their favorable health benefits. The present research focused on quantification of phytosterols as free, esterified and total forms in different tetraploid (5 cultivars of Triticum durum Desf., 9 cultivars of Triticum dicoccon Schrank) and hexaploid (5 cultivars of T. aestivum L., 12 cultivars of Triticum spelta L.) wheats. Tetraploid wheats showed the highest content of total sterol (79.4 and 79.5 mg of sterols /100 g dry weight for T. durum and T. dicoccon, respectively). Hexaploid cultivars were the best source of esterified sterols (40.7% and 37.3% of total sterols for Triticum aestivum and T. spelta, respectively). Significant amounts of free sterols (65.5% and 60.7% of total sterols for T. durum and T. dicoccon, respectively) were found in the tetraploid cultivars. The most abundant phytosterol in all wheat samples was sitosterol accounting for 45.1-59.1, 46.6-57.4 and 38.6-59.5% of total, free and esterified sterol fraction, respectively. These results demonstrate that although the sterol profile present in tetraploid and hexaploid wheat species is the same, differences in their relative amounts and distribution allow statistical differentiation between hexaploids and tetraploids, and between soft and durum wheats.

Cholesterol photosensitised oxidation of beef meat under standard and modified atmosphere at retail conditions.

The effect of the fluorescent light exposure and type of packaging (normal atmosphere and oxygen-rich atmosphere) was evaluated on the oxidation parameters (peroxides and cholesterol oxidation products) of raw beef slices placed in packed vessels and refrigerated. The concentration of COPs in meat treated under modified atmosphere ranged from 0.15 to 0.52mg/100g meat (average value of 0.27mg COPs/100g meat), which was twice as much as the average COPs content (0.14mg/100g) of meat packed under air (0.04-0.27mg COPs/100g meat). The main cholesterol oxide was 7k, which represented about one third of the total cholesterol oxides, followed by 7β-OH (20-25% of total COPs), 7α-OH (about 20%) and β-epoxy (12-18%). In normal atmosphere, photoxidation was a superficial process, since an inverse correlation between meat slice weight and COPs content on a lipid basis was observed, unlike in a high oxygen (32%) atmosphere.

CZE separation of strawberry anthocyanins with acidic buffer and comparison with HPLC.

Anthocyanins, the major colourants of strawberries, are polar pigments that are positively charged at low pH. Herein, we have assessed a new analytical method for the separation of anthocyanins using CZE. Acidic buffer solutions (pH <2) were employed in order to maintain pigments in the cation flavylium form and achieve high molar absorptivity at 510 nm. These spectral properties enabled us to identify strawberry anthocyanins in a preliminary stage by detection in the visible range, although the method was optimised at 280 nm to obtain the best S/N. The effects of buffer composition highlighted the necessity of adding an organic modifier to the running buffer to obtain a suitable separation. The electrophoretic method permitted the separation of the three main anthocyanins of strawberry extracts, namely pelargonidin 3-glucoside (Pg-glu), pelargonidin 3-rutinoside and cyanidin 3-glucoside. The electrophoretic results, expressed as retention time and separation efficiency of the major anthocyanin (Pg-glu), were compared to those achieved in HPLC, the analytical technique traditionally used for the investigation of anthocyanins in vegetable matrix. The content of Pg-glu in strawberries (cv. Camarosa), calculated with HPCE and HPLC methods, resulted respectively in 11.41 mg/L and 11.37 mg/L.