The content of phenols and ascorbic acid of the phenolic fraction, and carotenoids, tocopherols and capsaicinoids of the oily fraction from sweet bell peppers from northwest Mexico was determined. Antioxidant activity in both fractions was evaluated (ABTS and DPPH methods). Green cultivar had the highest content of phenols, flavonoids, and ascorbic acid and highest antioxidant activity. α-Tocopherolwas found in the four cultivars; however, capsaicinoids were not detected. The phenolic fraction had higher antioxidant activity than the oily fraction.
The phenolic compounds of Thompson grape bagasse were extracted using a 95:5 (vol/vol) ethanol/water mixture. Measurement of the antioxidant activity in refined soybean oil of bagasse grape extract was performed by using two different methods, the Rancimat method and the Schaal oven method in conjunction with peroxide value determination. The antioxidant activity of the extract was compared to the tertiary butyl hydroquinone (TBHQ) and butylated hydroxyanisole (BHA) activity. The bagasse grape extract showed similar antioxidant activities in both methods employed. At all concentrations tested [0.1, 0.3 and 0.5% of total phenols (TP)] the extract exhibited appreciable activity, which exceeded the activity of BHA. At some concentrations (0.3 and 0.5% TP) the extract exhibited activity comparable to that of TBHQ. Bagasse is a byproduct with a high content of phenolic compounds and is a good source of natural antioxidants.
Resveratrol is a naturally occurring polyphenol, well known as a nutritional supplement due to its strong antioxidant properties associated with anti-inflammatory activity and possible prevention of cardiovascular diseases. In this work, the effect of resveratrol on thermal, thermooxidative, and photo-oxidative degradation of polylactide is reported in the frame of developing fully biobased polymer formulations. Characterization of PLA films by thermal methods and photo-oxidative treatments demonstrated that resveratrol catalyzed high temperature transesterification reactions under inert atmosphere, whereas it efficiently inhibited the exothermal oxidative reactions of the polymer backbone. Lowtemperature photochemical degradation experiments on PLA films allowed elucidating the stabilization mechanisms of the phenolic additive. Resveratrol is capable of slowing the oxidative chain reaction of PLA through a peroxyl radicals scavenging mechanism, while it has little effect on the direct photolytical cleavage of the ester bonds. Moreover, direct resveratrol oxidation as well as the reaction between the phenol and photo-oxidized polymer species yield secondary photoproducts, which are also able to protect PLA against photo-oxidation likely due to the UV screening effect of the formed chromophores. Resveratrol is thus proposed as an eco-friendly and biocompatible additive for a sustainable approach to the stabilization of PLA films in packaging and other applications.
The fruit of the chiltepin [Capsicum annuum L. var. glabriusculum (Dunal) Heiser and Pickersgill] is considered an important genetic resource for pepper crop improvement. The chiltepin is distributed from Colombia, Central America, and Mexico to the southwestern United States. The present review provides a synopsis of the taxonomic classification of the genus Capsicum and the chiltepin and studies were conducted to explore the current genetic diversity of this resource and the urgent necessity for conservation programs. Additionally, brief information regarding the recent sequencing of the chiltepin genome is provided, which contributes important data that could assist in its genetic improvement and conservation. Furthermore, this review discusses the phytochemical compounds of the chiltepin. The revised information shows that the chiltepin is an important genetic resource for pepper crop improvement and a primary source of phytochemical compounds.
Recovery of functional molecules
from byproducts of agro-food industries
is an appealing approach to waste reduction and to obtain safe and
value-added phytochemicals with antioxidant and antimicrobial properties.
However, more information about the operational costs is needed for
successful industrial scale-up. In this study, the potential of pecan
(Carya illinoinensis) nutshell (NS) as a source of
antioxidants was investigated. To this aim, a hydroalcholic NS extract
(NSE) was thoroughly characterized, and its effect was investigated
on thermo- and photo-oxidative stability of two polymers widely used
in food packaging, polylactic acid (PLA) and polyethylene (PE). Twenty-six
phenolic constituents, including proanthocyanidins, were identified
in NSE, and its effective radical scavenging capacity was assessed.
NSE acted as a thermal stabilizer for PLA and PE films, both in an
oxygen-depleted environment (i.e., during melt processing) and in
the presence of oxygen during polymer service life. NSE showed great
potential as a PLA stabilizer, due to the compatibility with the polyester
matrix. Under UV-light irradiation, NSE was more effective in protecting
PE than PLA, due to combination of peroxy radical scavenging and inhibition
of Norrish-type photolytic cleavage. Finally, from the experimental
data, an economic evaluation of batch and continuous mode NSE manufacturing
was performed, demonstrating that the process is technically and economically
viable. Overall, these results emphasize the potential of NSE as a
low-cost, safe, and sustainable additive for the stabilization of
polymer films in packaging and other applications.
The purpose of this study was to evaluate the trans fatty acid (TFA) composition and the tocopherol content in vegetable oils produced in Mexico. Sample oils were obtained from 18 different oil refining factories, which represent 72% of the total refineries in Mexico. Fatty acids and TFA isomers were determined by gas chromatography using a 100-m fused-silica capillary column (SP-2560). Tocopherol content was quantified by normal-phase high-performance liquid chromatography using an ultraviolet detector and a LiChrosorb Si60 column (25 cm). Results showed that 83% of the samples corresponded to soybean oil. Seventy-two percent of the oils analyzed showed TFA content higher than 1%. Upon comparing the tocopherol contents in some crude oils to their corresponding deodorized samples, a loss of 40-56% was found. The processing conditions should be carefully evaluated in order to reduce the loss of tocopherols and the formation of TFA during refining.
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