Characterization, feasibility and optimization of Agaricus subrufescens growth based on chemical elements on casing layer.

The aim of this study was to analyze yields, biological efficiency, earliness (expressed as days to first harvest), and precociousness and establish models for the mushroom growing according to these parameters. The experiment followed a double factorial design with four sources of calcium (calcitic limestone, calcitic limestone + gypsum, dolomitic limestone and dolomitic limestone + gypsum) and 2 application times (25 days before casing and at the moment of casing), with 4 replicates for each treatment. Different calcium sources influenced differently Agaricus subrufescens production, especially as regards earliness, which showed significantly higher values when dolomitic limestone with gypsum was applied. Yield and biological efficiency were negatively correlated with H + AL, organic matter and Mg amount. Furthermore, earliness was positively correlated with H + Al, organic matter, and the amount of Mg and Fe. Finally, negative correlations were observed between precociousness and the amount of Ca, SB (sum of base), CEC (cation exchange capacity) and V% (percentage of base saturation). The models presented in this work are extremely important for predicting the agronomic performance of Agaricus subrufescens on the basis of chemical analysis provided by the casing soil.

Influence of the paprika type on redness loss in red line meat products.

Paprika, with its high colourant power (measured in ASTA units), imparts higher initial redness to fresh red sausage and fresh chorizo (red line meat products). This higher degree of redness (measured according to the red-green component, a∗, and spectrophotometric colour units) is maintained until the end of the products' shelf life. However, the pasteurization necessary to reduce the microbial load of paprika can cause alterations to its stability. The addition of natural antioxidants to pasteurized paprika (rosemary extract) was seen to maintain the colour levels of meat products throughout their shelf life. Differences in the colour of meat batches elaborated with paprika of different colourant power could be detected by consumers in a hedonistic test, who evaluated the colour positively.

Purification and characterization of a mannan-binding lectin specifically expressed in corms of saffron plant (Crocus sativus L.).

Despite the economical interest of Crocus sativus, its biochemistry has been poorly studied. Herein, we have isolated a lectin present in saffron corm by gel-filtration, anion-exchange, and reversed-phase chromatography. One- and two-dimensional PAGE, MALDI-MS, and N-terminal amino acid sequence analyses indicated that the native protein forms noncovalently linked aggregates of about 80 kDa apparent molecular mass, mainly composed of two charged heterogeneous (pI's, 6.69-6.93) basic subunits of approximately 12 kDa. Their N-terminal sequences shared 25% similarity and were homologous to the N- and C-terminal domains of monocotyledonous mannose-binding lectins, respectively. An additional polypeptide of around 28 kDa apparent molecular mass was also detected, probably corresponding to a precursor processed into two mature subunits. In addition, the N-terminal domain subunit exhibited 56% similarity with curculin, a sweet protein with taste-modifying activity. The native lectin specifically interacts with a yeast mannan and is a major corm protein specifically expressed in this organ.

Production of a cytotoxic proteoglycan using callus culture of saffron corms (Crocus sativus L.).

Saffron corms have been demonstrated to contain a proteoglycan that inhibits growth of human tumor cells. In this study, we show strong evidence indicating that callus cultures of saffron corm also synthesize such glycoconjugate. This compound is cytotoxic against human cervical epithelioid carcinoma cells (IC50 = 7 mg ml-1), and consists of approximately 90% carbohydrate and 10% protein. In order to optimize the glycoconjugate purification to complete functional and therapeutic studies, we have designed an improved method consisting of anion-exchange chromatography and reversed-phase HPLC, which can be easily scaled-up.