Quality Characteristics, Sensory Profiles and Ethylene Production of Stored 'Abate Fetel' Pears Sorted at Harvest by Time-Resolved Reflectance Spectroscopy.

Time-resolved reflectance spectroscopy (TRS), a nondestructive technique, can help the industry to provide high-quality fruit to encourage pear consumption. The absorption coefficient measured by TRS at 670 nm (µa670) represents a maturity index for pear fruit, with less mature pears high µa670 and more mature low µa670. The aim of this work was to study the quality characteristics, the sensory profiles and the ethylene production of 'Abate Fetel' pears sorted at harvest in different TRS maturity classes and stored in different atmospheres. At harvest, 540 pears were measured by TRS for µa670, ranked by µa670 in three maturity classes (less-LeM, medium-MeM and more-MoM mature) and randomized in nine samples according to 1-MCP treatment (treated, control), storage time (4-6 months) and atmosphere (air-NA; CA: 8-12 kPa O2, 1 kPa CO2). Fruits were examined at harvest and after 7 days of poststorage shelf life for skin color, firmness, soluble solids, acidity and ethylene production and were submitted to sensory analysis. At harvest and after storage, MoM pears were less green and showed a higher SSC content than LeM ones. After storage, MoM pears produced less ethylene and were perceived to be firmer (especially in 1-MCP-treated pears), more astringent and less juicy (when stored for 6 months) than LeM ones.

Pasta supplemented with isolated lupin protein fractions reduces body weight gain and food intake of rats and decreases plasma glucose concentration upon glucose overload trial.

The supplementation of foods with biologically active compounds can be a powerful approach for improving diet and well being. In this study we separately included in pasta matrices a concentrate of γ-conglutin, a glucose-lowering protein from Lupinus albus seeds, an isolate of the other main lupin storage proteins and ovalbumin, at a ratio corresponding to 125 mg of pure protein in 100 g of pasta. With these products we fed rats made hyperglycaemic, for 3 weeks. Among the most relevant changes measured in body and blood parameters were: (i) a significant reduction in food intake of rats fed γ-conglutin concentrate supplemented pasta and a significant limitation in the body weight increase in rats fed α, ß and δ-conglutin isolate supplemented pasta, while the food conversion indices were unchanged; (ii) a reduction in glycaemia upon glucose overload trial, especially in the γ-conglutin concentrate supplemented pasta fed animals, at a dose of 45 mg per kg body weight. The correlations among the measured parameters are discussed. Overall, the results evidence the potentiality of supplementing traditional foods with exogenous nutraceutical seed proteins to control body weight gain and glycaemia.

Effects of barley ß-glucan-enriched flour fractions on the glycaemic index of bread.

The aim of this research was to evaluate ß-glucan-enriched flours, obtained from barleys with either normal or waxy starch, for their effects on the glycaemic index (GI) and the quality of bread. Rheological results confirmed that when barley flour was included in the dough the overall quality of bread slightly worsened. However, positive consequences on glycaemia were obtained with the normal starch barley: the GI of all-wheat bread (82.8 ± 7.2) was significantly reduced (57.2 ± 7.9) when 40% of wheat flour was substituted with ß-glucan-enriched barley flour (6.0% ± 0.1 ß-glucan in the final flour blend). In contrast, this positive effect was significantly reduced (GI: 70.1 ± 9.1) when 40% of wheat flour was substituted with the ß-glucan-enriched flour of a waxy barley (CDC Alamo; 6.6 ± 0.2 ß-glucan in the final flour blend), suggesting that the ability of ß-glucans to lower the GI was affected by the barley starch-type.

Immunoreactivity of antibodies against transglutaminase-deamidated gliadins in adult celiac disease.

BACKGROUND: The significance of the presence of anti-gliadin antibodies in patients affected by celiac disease is still unclear. It is hypothesized that gliadin deamidation, catalysed by transglutaminase, plays a role in favoring the antigen presentation. AIM: To determine the immunoreactivity of anti-gliadin antibodies from untreated celiac patients to transglutaminase deamidated gliadins. MATERIALS AND METHODS: Gliadins from wheat flour underwent enzymatic digestion and were deamidated or cysteamine-transamidated by transglutaminase. Immunoreactivity of anti-gliadin antibodies from untreated adult celiac patients sera was evaluated by means of a competitive enzyme-linked immunosorbent assay (ELISA) method. RESULTS: Gliadin deamidation increased antibodies immunoreactivity from 25% to 50% while cysteamine incorporation into the gliadin peptides resulted in an immunoreactivity decrease. CONCLUSIONS: Increased immunoreactivity of transglutaminase deamidated gliadins tested with anti-gliadin antibodies from untreated adult celiac patients supports the hypothesis of a pivotal role of gliadin deamidation in the pathomechanism of celiac disease.

Celiac-related properties of chemically and enzymatically modified gluten proteins.

The effects of chemical (acid-heating treatment) and enzymatic (microbial transglutaminase, TGase) modification (deamidation) of gluten proteins on their physicochemical and celiac disease-related properties were studied. Ammonia release, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and sample solubility analyses were employed to check the extent of gluten modification. Among different treatments achieved, the acid-heating treatment performed at 90 degrees C for 3 h induced gluten deamidation, paralleling an increase of gluten solubility without relevant proteolysis. Changes in the immunoreactivity of celiac IgA anti-gliadin antibodies (AGAs) to modified gluten proteins were detected by using a competitive indirect enzyme-linked immunosorbent assay method. Chemical deamidation by acid-heating treatment of gluten lowered IgA-AGA immunoreactivity. IgA-AGA immunoreactivity to gliadins was increased when they were submitted to TGase-catalyzed deamidation. The acid-heating treatment of gluten reduced its cytotoxic activity on human colon adenocarcinoma LoVo cell line. These results showed that chemical deamidation of gluten may be envisaged as a way to lower the potential risk for celiac people due to widespread use of gluten as a food additive.