Bioaccessibility of carotenoids, vitamin A and α-tocopherol, from commercial milk-fruit juice beverages: Contribution to the recommended daily intake

Juices and By-Products of Red-Fleshed Sweet Oranges: Assessment of Bioactive and Nutritional Compounds

The content of nutrients and bioactive compounds, and antioxidant capacity were assessed in the juices from two red-fleshed oranges, Cara Cara and Kirkwood, and compared with that of a standard Navel orange. Two juice extraction procedures, hand-squeezing and industrial, and two treatments, pasteurization (85 °C/30 s) and high-pressure homogenization (HPH, 150 MPa/55 °C/1 min), were evaluated. For most of the nutrients and bioactive compounds, the hand and industrial juice squeezing rendered similar extraction efficiency. Individual composition of carotenoids in the juices were differentially affected by the extraction procedure and the treatments, but the red-fleshed orange juices contained between 3- to 6-times higher total carotenoids than the standard Navel juices, being phytoene and phytofluene the main carotenoids. The industrial and treated juices of both red-fleshed oranges contained 20-30% higher amounts of tocopherols but about 20% lower levels of vitamin C than Navel juices. Navel juices exhibited higher hydrophilic antioxidant capacity, while the red-fleshed orange juices showed an improved lipophilic antioxidant capacity. The main distinctive characteristic of the industrial juice by-product of the red-fleshed oranges was a higher content of carotenoids (×10) and singlet oxygen antioxidant capacity (×1.5-2) than the Navel by-product.

Assessment of in vitro bioaccessibility of carotenoids and phenolic compounds in a model milk-mandarine beverage

Mandarine juice is one of the richest sources of β-cryptoxanthin and flavonoids, which have been positively associated with bone mineral density. Carotenoids are lipophilic isoprenoid compounds with a complex absorption process that can be affected by different factors. In this study, we have evaluated the effect of the food matrix on the in vitro bioaccessibility of carotenoids and phenolic compounds in a model milk-mandarine beverage (MMB). MMBs were formulated with mandarine juice and different dairy products to achieve three fat levels (0.2%, 1.7% and 3.2%) and three calcium levels (120, 310 and 500 mg Ca²⁺ per 100 ml). The bioaccessibility was evaluated using a harmonised in vitro digestion method. The results showed that the content of milk fat increased the bioaccessibility in vitro of phenolic compounds (p < 0.05), while a moderate fat level (1.7%) resulted in the highest bioaccessibility for bioactive carotenoids. On the other hand, calcium fortification at the highest level (500 mg Ca²⁺ per 100 mL) decreased the bioaccessibility of bioactive carotenoids from 76% to 43% (66% for the major β-cryptoxanthin) compared to the lower calcium fortification level (120 mg Ca²⁺ per 100 mL). The bioaccessibility of hesperidin, the main flavanone in mandarine juice, was significantly (p < 0.05) reduced in the MMB with the highest calcium level. The bioaccessibility of carotenoids and phenolic compounds is affected by fat and calcium levels. When formulating functional beverages, the impact of the formulation should be carefully considered to optimize the bioaccessibility of the bioactive compounds.

Functional and Nutraceutical Compounds of Tomatoes as Affected by Agronomic Practices, Postharvest Management, and Processing Methods: A Mini Review

Tomatoes and their by-products are indisputable sources of substances with antioxidants properties. Several factors limit the production and influence the nutritional and antioxidant quality of tomato fruit. However, consumers can benefit from the effects of environmental factors, such as water and hydric stress, UV radiation, agronomic practices, among others, which lead to changes in the content of secondary metabolites in tomatoes. Molecules as phenolic compounds, carotenoids, and biogenic amines are often formed in response to environmental adversities. In this way, the consumption of tomato fruits or their by-products with higher levels of antioxidants may be important adjuvants in the prevention or reduction of diseases. In this mini-review, we will present how pre- and postharvest conditions may influence the content of some bioactive compounds in tomatoes. Furthermore, we will present how some heat processing methods may change the antioxidant content, as well as, the functional and nutritional properties of the final product.

Micelle separation conditions based on particle size strongly affect carotenoid bioaccessibility assessment from juices after in vitro digestion

For assessing the carotenoid bioaccessibility during in vitro digestion, obtaining the micelle fraction that can diffuse through the mucin layer according to the particle size is an important step. However, the accuracy of the various approaches to obtaining the right fraction of micelles described in literature has not been investigated. In many studies the reported bioaccessible fraction might therefore be over- or underestimating the real bioaccessibility. The present study aimed to fill this gap and give approaches to get accurate data on the bioaccessible fraction from samples with different properties. Results illustrated that optimizing the centrifugal speed and duration of the digesta are essential in obtaining the micelle fraction. Different digesta have different optimum centrifugal parameters to obtain the bioaccessible fraction. 6,000 rpm and 40 min was selected as the optimum centrifugal parameter for combined juice (CJ). 6,000 rpm and 60 min was the optimum centrifugal parameter for CJ with oil, and CJ with emulsion using non-ionic emulsifier. 8,000 rpm and 20 min was the optimum centrifugal parameter for CJ with emulsion using ionic emulsifier. Polygalacturonanase (PG)-digested systems required higher centrifugal speed (10,000 rpm) compared with CJ-based systems (6,000 rpm or 8,000 rpm). A prediction model to determine the optimal centrifugation speed/time from the properties of the intestinal digesta was developed. Sample preparation conditions strongly affect carotenoid bioaccessibility assessment from juices during in vitro digestion. Based on these results, it is highly recommended to perform an optimized preparation procedure for bioaccessible fraction prior to carotenoid bioaccessibility analysis.

Consumer-perception, nutritional, and functional studies of a yogurt with restructured elderberry juice

We investigated the effects of supplementation of yogurt with elderberry juice (Sambucus nigra L.), in both natural and restructured forms, on certain technological, physicochemical, sensory, and health-promoting properties of yogurt, including antioxidant activity and inhibition of angiotensin-converting enzyme (ACE), α-amylase, and α-glucosidase activity. Consumer acceptance of the yogurt-juice products was assessed. Gel-strength restructured elderberry juice retained a spherical shape and most of the juice, despite decreasing in mass from 57.2 to 50.9 g during storage. As a result, yogurt supplemented with 10 and 25% restructured elderberry juice appeared to be more desirable from a sensory and technological perspective than yogurt with natural juice. Yogurt supplemented with restructured elderberry juice had a high water-holding capacity (94.4-96.4%), exhibited no spontaneous whey syneresis, and maintained a dense consistency (up to 5,626 g). Consumer penalty analysis of the just-about-right diagnostic attributes indicated that the flavor of these yogurts may not be sufficiently refreshing. High correlation was demonstrated between ACE inhibition, ABTS, α-amylase, and α-glucosidase in yogurt supplemented with restructured juice. An in vitro gastrointestinal simulation estimated bioaccessibility of antioxidants to be in the range of 62 to 66%. This model fermented yogurt supplemented with restructured elderberry juice is a novel dairy-juice beverage that represents a new approach for the development of functional fruit yogurt beverages.

A fast and simple method for determination of β-carotene in commercial fruit juice by cloud point extraction-cold column trapping combined with UV-Vis spectrophotometry

Cloud point extraction with cold column trapping (CPE-CCT) was used for the rapid preconcentration and UV-Vis spectroscopy of beta-carotene in fruit juice samples. A central composite design was employed to optimize parameters such as pH, incubation time, cloud point temperature and surfactant concentration. A detection limit of 0.01 mg/L of beta-carotene (3S_B/m), a coefficient of determination of 0.998 and a linear range of 0.04-10 mg/L were obtained. The CPE-CCT method was confirmed in comparison with the corresponding direct HPLC standard method. A simple, portable and cost-effective device was also utilized. Owing to eliminating centrifugation, the conditions of CPE-CCT were more moderate and its sample handling easier compared to conventional CPE.

A Brief Overview of Dietary Zeaxanthin Occurrence and Bioaccessibility

As it exhibits no provitamin A activity, the dietary intake of zeaxanthin is not considered essential. However, its contribution to ocular health has long been acknowledged. Numerous publications emphasize the importance of zeaxanthin alongside lutein in ocular diseases such as cataracts and age-related macular degeneration which constitute an important health concern, especially among the elderly. Considering that the average dietary ratio of lutein to zeaxanthin favors the first, more bioaccessible food sources of zeaxanthin that can hinder the development and progression of the above-mentioned disorders are of great interest. In this paper, a brief overview of the more recent state of knowledge as regards dietary sources together with their respective zeaxanthin bioaccessibility assessed through a standardized in vitro digestion method was provided.

Influence of high pressure homogenization and pasteurization on the in vitro bioaccessibility of carotenoids and flavonoids in orange juice

Production of high-quality healthy foods through sustainable methodologies is an urgent necessity. High pressure homogenization (HPH) is an interesting alternative to obtain premium citrus juices, but its effects on bioactive compounds are unclear. There was studied the influence of HPH (150 MPa) and pasteurization (92 °C for 30 s and 85 °C for 15 s) processing on physicochemical properties and in vitro bioaccessibility of carotenoids and flavonoids in orange juices. Regarding fresh juice, physicochemical properties of samples remained unchanged although cloudiness was improved by homogenization. Pasteurization did not affect total carotenoids content and retinol activity equivalents (RAE) of juices whereas homogenization yielded a significant reduction (1.37 and 1.35-fold, respectively). Interestingly, particle size reduction from homogenization drastically enhanced (about 5-fold) bioaccessibility of carotenoids including hardly bioaccessible epoxycarotenoids, finding unaltered rates in pasteurized samples. Bioaccessibility of flavonoids was constant in all cases. Results can promote HPH as an efficient option to obtain health-enhanced foods.

Extraction and Analysis by HPLC-DAD of Carotenoids in Human Faeces from Spanish Adults

Carotenoids are bioactive compounds with widely accepted health benefits. Their quantification in human faeces can be a useful non-invasive approach to assess their bioavailability. Identification and quantification of major dietary carotenoids in human faeces was the aim of the present study. Faeces and dietary intake were obtained from 101 healthy adults (45-65 years). Carotenoid concentrations were determined by HPLC in faeces and by 3-day food records in dietary intake. Carotenoids quantified in faeces (µg/g dry weight, median) were: β-carotene (39.5), lycopene (20), lutein (17.5), phytoene (11.4), zeaxanthin (6.3), β-cryptoxanthin (4.5), phytofluene (2.9). α-carotene (5.3) and violaxanthin were found 75.5% and 7.1% of the faeces. The carotenoids found in the highest concentrations corresponded to the ones consumed in the greatest amounts (µg/d): lycopene (13,146), phytoene (2697), β-carotene (1812), lutein+zeaxanthin (1148). Carotenoid concentration in faeces and in dietary intake showed correlation for the total non-provitamin A carotenoids (r = 0.302; p = 0.003), phytoene (r = 0.339; p = 0.001), phytofluene (r = 0.279; p = 0.005), lycopene (0.223; p = 0.027), lutein+zeaxanthin (r = 0.291; p = 0.04) and β-cryptoxanthin (r = 0.323; p = 0.001). A high proportion of dietary carotenoids, especially those with provitamin A activity and some of their isomers, reach the large intestine, suggesting a low bioavailability of their intact forms.

Bile amount affects both the degree of micellarization and the hydrolysis extent of carotenoid esters during in vitro digestion

Carotenoid esters are present in considerable amounts in most fruits, such as in citrus. Although the bioavailability of carotenoid esters is similar or even higher compared to that of free carotenoids, these molecules are generally detected only in the free form in human plasma, suggesting that hydrolysis of carotenoid esters occurs in vivo. However, the available in vitro digestion methods were not able to achieve satisfactory carotenoid ester hydrolysis so far. As bile salts play an essential role in the hydrolytic action of lipolytic enzymes from pancreatin, we evaluated the effect of increasing the bile extract/food ratio from 0.045 to 0.12 (g g-1) on the hydrolysis of β-cryptoxanthin esters from mandarin pulp during in vitro digestion. Additionally, considering the positive effect of lipids on carotenoid bioavailability, the impact of soybean oil addition on carotenoid ester hydrolysis was studied. Finally, bioaccessibility and recovery of 33 carotenoids were assessed by LC-DAD-MS. The hydrolysis extent of β-cryptoxanthin esters enhanced from 29% to 55% by increasing the bile extract/food ratio, but reduced respectively to 28% and 11% by the addition of 1% and 10% oil (p < 0.05). The bioaccessibility of overall carotenoids improved from 19% to 35% by increasing the bile extract/food ratio, along with that of (all-E)-β-carotene (from 19 to 31%) and total (all-E)-β-cryptoxanthin (17% to 49%). Soybean oil addition reduced carotenoid micellarization, regardless of the concentration (p < 0.05). Irrespective of the bile extract amount and oil addition, the bioaccessibility of carotenoids was inversely related to its hydrophobicity, with respect to the following ranking: free xanthophylls > carotenes ≥ xanthophyll esters. Altogether, these results indicate that increasing the bile extract amount is a simple and inexpensive option to improve carotenoid ester hydrolysis in in vitro digestion protocols. Additionally, the constant amounts of bile (and possibly enzymes) of static methods, such as INFOGEST, should be further optimized for experiments involving lipid addition in which carotenoid bioaccessibility is evaluated.