Identification and quantification of fatty acids and lipid-soluble phytochemicals using GC-MS, HPLC-MS, and FTIR and their association with quality parameters during avocado ripening.

Consumer demand for the avocado fruit has increased considerably, but accelerated fruit ripening, lack of fruit ripening uniformity, and lack of proper quality characteristics and indices generate considerable problems during fruit handling and trade. Physicochemical parameters are used to determine avocado fruit ripening. These parameters together with lipid-soluble phytochemicals (LSP) and fatty acids (FAs) highlight the health and economic importance of this fruit. Analysis of LSP and FAs in avocado fruit has been reported, but combining the use of analytical techniques such as Fourier transform infrared spectroscopy (FTIR), gas chromatography-mass spectrometry (GC-MS), and high-pressure liquid chromatography coupled to mass spectrometry (HPLC-MS) to determine qualitative and quantitative changes during fruit ripening, and their association with physicochemical parameters, has not been conducted. Physicochemical parameters (fruit firmness, color, oil and dry matter contents) were determined, and the changes of FAs and LSP (carotenoids, chlorophylls, and tocopherols) during "Hass" avocado ripening, based on dry matter (DM) content, were analyzed using FTIR, GC-MS, and HPLC-MS. The association between them was also determined using principal component analysis. Fruit with 19% and 25% DM exhibited high LSP and FAs levels. Carotenoids, chlorophylls, and tocopherols were associated with firmness, color, and DM of 19% and 22%, while FAs were associated with fruit weight and DM of 25%. PRACTICAL APPLICATION: There is a major global increase in avocado cultivation and consumer demand. However, a major problem facing the handling and trade of avocado fruit is related to lack of fruit ripening uniformity and quality characteristics and indices. Therefore, a proper association between simple measures of fruit physicochemical properties and bioactive components can establish an excellent, simple, and practical index that can eventually be used for quality evaluation by the industry and the consumers.

Avocado oil: Production and market demand, bioactive components, implications in health, and tendencies and potential uses.

Avocado is a subtropical/tropical fruit with creamy texture, peculiar flavor, and high nutritional value. Due to its high oil content, a significant quantity of avocado fruit is used for the production of oil using different methods. Avocado oil is rich in lipid-soluble bioactive compounds, but their content depends on different factors. Several phytochemicals in the oil have been linked to prevention of cancer, age-related macular degeneration, and cardiovascular diseases and therefore have generated an increase in consumer demand for avocado oil. The aim of this review is to critically and systematically analyze the worldwide production and commercialization of avocado oil, its extraction methods, changes in its fat-soluble phytochemical content, health benefits, and new trends and applications. There is a lack of information on the production and commercialization of the different types of avocado oil, but there are abundant data on extraction methods using solvents, centrifugation-assisted aqueous extraction, mechanical extraction by cold pressing (varying concentration and type of enzymes, temperature and time of reaction, and dilution ratio), ultrasound-assisted extraction, and supercritical fluid to enhance the yield and quality of oil. Extensive information is available on the content of fatty acids, although it is limited on carotenoids and chlorophylls. The effect of avocado oil on cancer, diabetes, and cardiovascular diseases has been demonstrated through in vitro and animal studies, but not in humans. Avocado oil continues to be of interest to the food, pharmaceutical, and cosmetic industries and is also generating increased attention in other areas including structured lipids, nanotechnology, and environmental care.

Bioaccessibility of fat-soluble bioactive compounds (FSBC) from avocado fruit as affected by ripening and FSBC composition in the food matrix.

Dried fruit pulp and oil from avocado fruit (Persea americana, Cv Hass) at five different ripening stages were digested in vitro to determine the bioaccessibility of several fat-soluble bioactive compounds (FSBC). Viscosity, particle size, ζ-potential and lipolysis were evaluated and related to the bioaccessibility of the tested compounds. Fatty acids were more bioaccessible than carotenoids and tocopherols. The viscosity of gastrointestinal medium was related to the initial fruit firmness and modulated the bioaccessibility of neoxanthin, violaxanthin, lutein and luteoxanthin, while particle size and ζ-potential influenced the bioaccessibility of fatty acids. Lipolysis degree highly altered the bioaccessibility of luteoxanthin, pheophytin b, and α-tocopherol indicating that these digestive events are highly involved in the bioaccessibility of FSBC. In summary, FSBC from avocado fruit are highly bioaccessible, but their bioaccessibility depends on fruit ripening stage and FSBC type and concentration.

Effects of pectin on lipid digestion and possible implications for carotenoid bioavailability during pre-absorptive stages: A review.

Pectin, an abundant polysaccharide in the human diet, has structural characteristics and functional properties that are strongly dependent on the food matrix (e.g., origin, type, cultivar/variety, ripening stage, style and intensity of processing). These polysaccharides have a strong effect on lipid digestion, which is required for the liberation of carotenoids from emulsified lipid droplets in the gastrointestinal content and for the formation of micelles, in which the carotenoids must be incorporated before absorption. Only micellarized carotenoids can be absorbed and subsequently exert protective effects on human health. The alteration of lipolysis by pectin can occur through several mechanisms; however, they have not been linked directly to carotenoid micellarization. This paper provides an overview of the effects of the properties of pectin on the ion concentration in the digestive content, the viscosity of the digestive medium, the properties of the lipid droplet surfaces and lipase activity and analyzes the impact of these events on lipid digestion and subsequent carotenoid micellarization.

Absorption of Carotenoids and Mechanisms Involved in Their Health-Related Properties.

Carotenoids participate in the normal metabolism and function of the human body. They are involved in the prevention of several diseases, especially those related to the inflammation syndrome. Their main mechanisms of action are associated to their potent antioxidant activity and capacity to regulate the expression of specific genes and proteins. Recent findings suggest that carotenoid metabolites may explain several processes where the participation of their parent carotenoids was unclear. The health benefits of carotenoids strongly depend on their absorption and transformation during gastrointestinal digestion. The estimation of the 'bioaccessibility' of carotenoids through in vitro models have made possible the evaluation of the effect of a large number of factors on key stages of carotenoid digestion and intestinal absorption. The bioaccessibility of these compounds allows us to have a clear idea of their potential bioavailability, a term that implicitly involves the biological activity of these compounds.

Associations between whole peripheral blood fatty acids and DNA methylation in humans.

Fatty acids (FA) modify DNA methylation in vitro, but limited information is available on whether corresponding associations exist in vivo and reflect any short-term effect of the diet. Associations between global DNA methylation and FAs were sought in blood from lactating infants (LI; n = 49) and adult males (AMM; n = 12) equally distributed across the three conventional BMI classes. AMM provided multiple samples at 2-hour intervals during 8 hours after either a single Western diet-representative meal (post-prandial samples) or no meal (fasting samples). Lipid/glucose profile, HDAC4 promoter and PDK4 5'UTR methylation were determined in AMM. Multiple regression analysis revealed that global (in LI) and both global and PDK4-specific DNA methylation (in AMM) were positively associated with eicosapentaenoic and arachidonic acid. HDAC4 methylation was inversely associated with arachidonic acid post-prandially in AMM. Global DNA methylation did not show any defined within-day pattern that would suggest a short-term response to the diet. Nonetheless, global DNA methylation was higher in normal weight subjects both post-prandially and in fasting and coincided with higher polyunsaturated relative to monounsaturated and saturated FAs. We show for the first time strong associations of DNA methylation with specific FAs in two human cohorts of distinct age, diet and postnatal development stage.

The trans fatty acid elaidate affects the global DNA methylation profile of cultured cells and in vivo.

BACKGROUND: The deleterious effects of dietary trans fatty acids (tFAs) on human health are well documented. Although significantly reduced or banned in various countries, tFAs may trigger long-term responses that would represent a valid human health concern, particularly if tFAs alter the epigenome. METHODS: Based on these considerations, we asked whether the tFA elaidic acid (EA; tC18:1) has any effects on global DNA methylation and the transcriptome in cultured human THP-1 monocytes, and whether the progeny of EA-supplemented dams during either pregnancy or lactation in mice (n = 20 per group) show any epigenetic change after exposure. RESULTS: EA induced a biphasic effect on global DNA methylation in THP-1 cells, i.e. hypermethylation in the 1-50 µM concentration range, followed by hypomethylation up to the 200 µM dose. On the other hand, the cis isomer oleic acid (OA), a fatty acid with documented beneficial effects on human health, exerted a distinct response, i.e. its effects were weaker and only partially overlapping with EA's. The maximal differential response between EA and OA was observed at the 50 µM dose. Array expression data revealed that EA induced a pro-inflammatory and adipogenic transcriptional profile compared with OA, although with modest effects on selected (n = 9) gene promoter methylation. In mice, maternal EA supplementation in utero or via the breastmilk induced global adipose tissue DNA hypermethylation in the progeny, that was detectable postnatally at the age of 3 months. CONCLUSION: We document that global DNA hypermethylation is a specific and consistent response to EA in cell culture and in mice, and that EA may exert long-term effects on the epigenome following maternal exposure.

Effect of ripening and heat processing on the physicochemical and rheological properties of pepper pectins.

Water-, chelator-, and alkali-soluble pectins were isolated from raw and heat-processed Jalapeño peppers (green and red) and their physiochemical and rheological properties were determined. The yield, tristimulus color, degree of methyl esterification, monosaccharide composition, molecular weights distribution, and protein content depended on ripening and heat processing. The viscosity properties of pectins were independent of ripening. The water-soluble pectin was the most abundant pectin. Pectins from grilled peppers showed the lowest L* values. The alkali-soluble pectin showed the highest protein content. The content of xylose, rhamnose, and mannose in pectins was highly altered by tested factors. The degree of methyl esterification of pectins ranged from 26.8 to 91.6%. The peak Mw of the main fraction of tested pectins was sequentially reduced by ripening and heat processing. Pectins from raw peppers showed the best viscosity properties.

Antioxidant activity and content of chlorophylls and carotenoids in raw and heat-processed Jalapeño peppers at intermediate stages of ripening.

Jalapeño peppers at intermediate ripening stages (IRS) are typically discarded at the packinghouse because they are not demanded for fresh consumption or industrial processing. These peppers have been scarcely studied in terms of pigment composition and bioactivity. In this study, the profile of pigments (carotenoids and chlorophylls) and antioxidant activity were determined in raw and heat-processed Jalapeño peppers at three IRS (brown, 50% red, and 75% red). Peppers contained 64 different pigments. Chlorophylls were the most abundant pigments in raw brown peppers while capsanthin was the most abundant at the other IRS. The content of most pigments decreased due to heat treatments. Several pheophytins and cis isomers of carotenoids were generated by heat processing. Boiling and grilling consistently decreased and increased the antioxidant activity of peppers, respectively. Tested peppers showed a more complex/abundant pigment content and higher antioxidant activity than those typically reported for green and red peppers.

Effect of ripening, heat processing, and fat type on the micellarization of pigments from jalapeño peppers.

Raw and heat-processed (boiled and grilled) jalapeño peppers at three intermediate ripening stages (brown, 50% red, and 75% red) were digested in vitro without fat and in the presence of soybean oil (SO) or beef tallow (BT), and the micellarization of their lipid soluble pigments (LSP) was measured. The micelles from digestions with brown, 50% red, and 75% red peppers contained up to 27, 35, and 29 different LSP, respectively. Boiling and grilling decreased the micellarization of LSP from brown peppers, whereas the opposite was observed with 75% red peppers. Heat processing did not clearly affect the micellarization of LSP from 50% red fruits. The impact of fat on LSP micellarization was ripening-dependent, but the micellarization of the less polar carotenoids was always increased by SO or BT. This positive effect of fat was higher with SO than with BT.

Effect of heat processing on the profile of pigments and antioxidant capacity of green and red jalapeño peppers.

Raw and heat-processed jalapeño peppers (green and red) were evaluated for their pigment profile and antioxidant capacity. Sixty-seven pigments were separated and characterized by HPLC-DAD-MS, including carotenoids (isomers and esters), chlorophylls, and pheophytins. The distinctive characteristics of this pepper genotype were the presence of antheraxanthin monoesters, zeaxanthin monoesters, mutatoxanthin diesters, and a higher content of free capsanthin relative to the mono- and diesterified forms. Chlorophyll a and free all-trans-lutein were the major pigments in raw green peppers, whereas free all-trans-capsanthin was the most abundant pigment in raw red peppers. Twelve compounds were generated by the heat treatments, mainly pheophytins and cis isomers of carotenoids. Heat treatments affected differentially the concentration of individual pigments. Red peppers showed a higher antioxidant capacity than green fruits. Heating caused minor changes in the antioxidant capacity of peppers.