1,721,045 research outputs found
Teanina: un aminoacido emergente dal tè verde Theanine: an emerging amino acid from green tea
No full textTeanin
Glutamic Acid in Food and its Thermal Degradation in Acidic Medium
No full textGlutamic acid is an amino acid naturally occurring in many foods and it is responsible for umami taste. For this reason, it has been widely used as a food additive and flavor enhancer as monosodium glutamate. Glutamic acid is stable under standard conditions.
However, high temperature or extreme pH conditions may induce racemization. In addition, it is a good substrate for non-enzymic browning reactions (Maillard reaction).A case study of the glutamic acid thermal degradation at acidic pH was carried out. Different grape musts were subjected to heating at 90 °C for 30 h by means of a lab-scale equipment emulating a real process.
Model solutions were utilized to gain a deeper comprehension of this phenomenon and to explain the glutamic acid degradation pattern. Results showed that glutamic acid underwent degradation during grape must cooking, following the same trend observed in the model solutions.
The amino acid was almost linearly reduced throughout all the cooking procedure yielding pyroglutamic acid as the main product of degradation
Composition and applications of fractions discharged from a distillation plant for neutral ethanol production
No full textThe composition of the different fractions constituting a distillation plant for neutral ethanol production was analysed. Not only the fractions that are usually discarded from the plant (heads and fusel oils) were studied but also the ones that usually circulate within the plant, passing from one column to another, which are normally impossible to reach. It was thus possible to follow the path of each component inside the plant in order to observe where it accumulates and where is disposed of. The potential exploitation of these by-products and of the chemicals involved in the processing of neutral ethanol were taken into consideration and new approaches for their use, such as in fuel cell technology, were proposed
Influenza della composizione sulla qualità dell’Aceto Balsamico Tradizionale
No full textIn questo studio è stato considerato il ruolo di alcuni parametri sul profilo qualitativo dell’Aceto Balsamico Tradizionale (ABT). Sono stati determinati: acidità totale, pH, densità, °Brix, ceneri, acidi organici, zuccheri, composti furanici su diciannove ABT, precedentemente valutati mediante analisi sensoriale, e distinti per classe merceologica. Infine, è stata determinata l’attività antiradicalica del prodotto.L’elaborazione statistica dei dati ha rivelato che molti parametri (zuccheri, densità, residuo secco, ecc.) influenzano positivamente la qualità dell’aceto, mentre altri come l’acido acetico ha un’influenza negativa. Oltre a ciò, interessanti correlazioni hanno evidenziato che alcuni parametri (ceneri, polifenoli totali, attività antiradicalica, ecc.) sono possibili indici di qualità degli aceti.Tra contenuto di 5-(idrossimetil)-2-furaldeide (HMF) e acido lattico è stata, infine, evidenziata un’inattesa correlazione per la quale è stata proposta una spiegazione plausibile
UV-B light (radiation) affects the metabolism of pigments and fatty acids in green algae Edaphochlorella mirabilis and Klebsormidium flaccidum in vitro
Full text linkAlgae offer a rich source of bioactive compounds suitable for food products and bioenergy. Environmental challenges such as nutrient scarcity, extreme pH and temperature, high light intensity, and UV radiation usually trigger algae to produce excess of lipids, antioxidants, and other bioprotective molecules as part of their adaptations for survival. Algal cultivation provides proteins, lipids, carbohydrates, vitamins, antioxidants, and trace elements. This study focused on understanding how UV-B irradiance, as an abiotic stressor, can influence the growth and metabolite production of two green algal species, Edaphochlorella mirabilis (Chlorophyta) and Klebsormidium flaccidum (Charophyta). Using a temporary immersion system bioreactor for in-vitro algal growth, the results showed no significant difference in biomass for both algal species after the exposure to UV-B rays. However, the assessment of malondialdehyde levels revealed a significantly higher tendency towards lipid peroxidation in treated E. mirabilis (+ 90 %) compared to control. Conversely, K. flaccidum did not display significant differences, thereby highlighting a more advanced adaptive capacity against UV-B radiation. Overall, both algal species treated with UV-B showed increased pigment accumulation. K. flaccidum exhibited an average pigment increase of over 53 %, while E. mirabilis showed a lower increase, over 30 % on average. The notable rise in antioxidant compounds (lutein, β-carotene, and chlorophyll a) in UV-B exposed K. flaccidum samples also suggested a more suitable adaptive strategy to mitigate oxidative stress in Charophyta. In K. flaccidum, the increase in polyunsaturated fatty acids can be associated with increased production of antioxidant compounds. Conversely, E. mirabilis appeared to protect itself by decreasing polyunsaturated fatty acids in favor of saturated ones. In both algal species, the increase in secondary metabolites under UV stress highlighted potential as a novel food source for human consumption, deserving further investigation
Saba, A Traditional Grape Molasse From Italy: Preliminary Analytical Characterization in Comparison With Fruit Pekmez
No full textFruit juice molasses, from grapes, mulberries and many other fruits, still represent important
traditional food products from the Balkans to the Caucasus, where they are indicated as
“pekmez” and its linguistic variants. In Italy, grapes have always been primarily used for wine
production. However, locally available resources were fully exploited in the past: saba or sapa
is a grape molasse obtained from unfermented juice slowly boiled for 24-48 hours, to obtain
a brownish, dense, very sweet syrup, storable for long time. Saba was used as a food, to
accompany cereal gruels or bread and, in less restricted situations, to season meat, cheese,
and to prepare particular pastries (“tortelli”) and jams (“savor”). After being almost forgotten,
in recent years saba has been resumed and is nowadays produced by local firms throughout
central Italy, where it is also the subject of local festivals.
In this work basic physical and chemical traits of several commercial saba samples from
different areas of Italy were analyzed and compared to samples of pekmez from Turkey and
Armenia and sladko from Bulgaria.
Saba dry matter and soluble solid content were respectively 68% and 63%, with high
variability among samples. Average titratable acidity was 14.8 g TAEs/L. Pekmez and sladko
showed lower variability and higher average dry matter and Brix with respect to Italian saba,
probably because of the tendency to reduce cooking time and temperature by some processors
in Italy, in order to increase yield and avoid the production of unwanted molecules.
Acidity was more stable and less affected by cooking, allowing to relate the differences among
samples to raw materials (species or cultivars). Titratable acidity and pH were more variable
in pekmez than in saba as a consequence of the very different raw materials used (mulberry,
carob, pomegranate, grapes). Pomegranate pekmez had very high acidity
Studio della composizione antocianica in vitigni reggiani a bacca rossa
No full textIn questo studio è stato valutato il ruolo di alcuni parametri nella caratterizzazione compositiva di uve. I parametri °Brix, acidità titolabile, pH, contenuto totale di antociani, indici colorimetrici (L*, a*, b*, C, H), contenuto dei singoli antociani sono stati determinati in campioni appartenenti a quattro cultivar (cv.) di vitigni autoctoni reggiani a bacca rossa (Lambrusco salamino,Lambrusco Marani, Lambrusco grasparossa, Malbo gentile).L’elaborazione statistica dei dati ha rivelato che alcuni parametri,quali gli indici colorimetrici ed il contenuto di alcuni antociani,consentono la discriminazione dei diversi campioni e l’individuazione di costanti compositive importanti per definire le caratteristiche qualitative del vitigno e del prodotto che ne scaturisce
Short-time irrigation on young olive tree (Olea europaea L. cv. Chemlali) with untreated industrial poultry wastewater: investigation of growth parameters and leaves chemical composition
No full textThe purpose of this study was to evaluate the short-term irrigation effect with industrial poultry wastewater on young olive trees (Olea europaea L. cv. Chemlali). Industrial poultry wastewater can be considered as a bio-fertilizer due to its richness in nutritive elements (SO42−, HCO3−, total nitrogen, and K+). The physicochemical analysis of wastewater showed a high concentration of TSS, COD, BOD, COT, NO3−, and conductivity. Measurements indicated that poultry wastewater enhanced plant growth, leaves dry matter, and ashes in comparison with tap water, as well as poultry wastewater diluted with tap water; however, a decrease in total soluble sugars (glucose and fructose) was detected in leaves. The determination of fatty acid profile of young olive trees leaves irrigated with poultry wastewater showed richness on saturated fatty acids in comparison with mono- and poly-unsaturated ones. In addition, oleic acid (C18:1) presented the lowest content in leaves of trees irrigated with poultry wastewater irrigation. According to those results, poultry wastewater lends itself to being a hydric alternative and at the same time a source of nutrients that can help fill the water deficit in semi-arid countries and avoid costly waste disposal for slaughterhouses
Determination of phthalate esters in distillates by ultrasound-vortex-assisted dispersive liquid-liquid micro-extraction (USVADLLME) coupled with gas chromatography/mass spectrometry
Full text linkABSTRACT. A method for the extraction of phthalate esters (PAEs) by Ultrasound-Vortex-Assisted Dispersive
Liquid-Liquid Micro-Extraction (USVADLLME) approach was optimised and applied for the first time to
a historical series of brandies. These contaminants are widely spread in the environment as a consequence of about half century of use in different fields of applications. The concern about these substances
and the recent legal restrictions of China in distillates import need a quick and sensitive method for their
quantification. The proposed method, moreover, is environmentally oriented due to the disposal of
micro-quantities of solvent required. In fact, sub-ppm-limits of detection were achieved with a solvent
volume as low as 160 lL.
The analysed samples were within the legal limits, except for some very ancient brandies whose
contamination was probably due to a PAEs concentration effect as a consequence of long ageing and
for the use of plastic pipelines no more operative
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