Fresh-squeezed Juice Research Articles

Comparison of vitamin C and flavanones between freshly squeezed orange juices and commercial 100% orange juices from four European countries

Knowing the true levels of nutrients and dietary bioactives in fruit juices at the point of consumption is key to properly understand their potential health benefits. The objective was to characterise the vitamin C and flavanone content in commercial orange juices consumed in Europe, compared with fresh-squeezed juices. Commercial juices were a rich source of vitamin C (>30% of the Nutrient Reference Value). Vitamin C in fresh-squeezed juices, at the end of their shelf-life, remained 33% higher than the levels found in the commercial juices. Flavanones had similar values from both commercial and fresh juices, except for fresh samples stored for 48 h, where fresh juices had higher values (22.36 mg/100 mL). Thus, orange juices preserve their bioactive compounds during storage, with very little influence of the brand, country, industrial process or storage conditions. Main bioactive compounds in commercial juices are present at nutritionally significant levels to the freshly-squeezed ones.

Bioaccessibility of Betalains in Beetroot (Beta vulgaris L.) Juice under Different High-Pressure Techniques.

The influence of high hydrostatic pressure (HHP) and supercritical carbon dioxide (SCCD) on the bioaccessibility of betalains in beetroot (Beta vulgaris L.) juice was investigated. Freshly squeezed juice (FJ) was treated at a mild temperature of 45 °C for 10 min (T45), pasteurization at 85 °C for 10 min (T85), HHP at 200, 400, and 500 MPa at 20 °C for 5 min (HHP200, HHP400, HHP500) and SCCD at 10, 30 and 60 MPa at 45 °C for 10 min (SCCD10, SCCD30, SCCD60). The juice was subjected to an in vitro digestion system equipped with dialysis. The content of betalains was measured with the aid of a High-Performance Liquid Chromatography (HPLC), the antioxidant capacity (AC) (ABTS•+, DPPH•) was analyzed during each digestion step, and the bioaccessibility of betacyanins and betaxanthins was assessed. The SCCD at 30 and 60 MPa significantly increased pigments’ bioaccessibility compared with other samples. The 30 MPa proved particularly advantageous, as it increased the bioaccessibility of the total betacyanins and the betaxanthins by 58% and 64%, respectively, compared to the T85 samples. Additionally, higher bioaccessibility of betacyanins was noted in HHP200 and HHP400, by 35% and 32%, respectively, compared to FJ, T45, and T85 samples. AC measured by ABTS•+ and DPPH• assays were not unequivocal. However, both assays showed significantly higher AC in SCCD60 compared to T85 (21% and 31%, respectively). This research contributed to the extended use of the HHP and/or SCCD to design food with higher health-promoting potentials.

Great Expectations - Ask for what you want

A few years ago, I expected breakfast in bed on Mother’s Day. The day before, I dropped not-so-subtle hints so my husband Jason and my teenage girls would know what I wanted. When I awoke, I saw that Jason had already gotten up. Smiling, I listened to the clatter of pans and clinking of dishware from the kitchen. As the wait grew longer, my imagined breakfast grew more elaborate. Now I had a picture in my head of fresh-squeezed juice, a platter of French toast, a steaming mug of coffee, flowers, and a handwritten card.

Influence of the unfrozen magnetized water on juices

Influence of magnetic field on water has been described in the paper. The patented device constructed on the basis of a stator of three-phase asynchronous motor has been used for processing of water in the experiments.It has been found that the water, processed in the electromagnetic field contains less mineral salts, has bigger cell permeability, and is characterized by falling of reduction-oxidation potential, and also by decreasing of electromotive force of the system. Electro physical indices may be used for rapid estimation of sanitary effect of water which is processed in the rotating magnetic field, and it is used for dilution of fresh-squeezed juices. Such juices have more positive action on a human body in comparison with non-diluted ones.The electromotive force of the system, which correlated with the value of reduction-oxidation potential of the system, has been measured. The decreasing of electromotive force confirms the sanitary effect of pure magnetized water, as well as the mix of fresh-squeezed juices with magnetized water. One of the main disadvantages, which interferes with wide introduction of magnetized water into the institutions, which are not equipped with special equipment, is the gradual loss of the obtained by the water properties with time. The results of the investigation show that the water threatened by electro magnetic field after freezing, low-temperature storage, and defrosting, preserves the obtained properties for a long time. It has been shown in the paper, that application of defrosted magnetic water for germination of seeds accelerates the processes of growth. Diluting of juices, such as apple, carrot, beat, and ash berry ones, by magnetized water, reduce of electro physical indices.

Non-Destructive Estimation of Mechanical and Chemical Properties of Persimmons by Ultrasonic Spectroscopy

Fruit properties, including ripeness, are still being measured destructively in most countries. Recently, an increased attention has been given to non-destructive methods, such as ultrasonic techniques, for quality assessment of food commodities. The aim of this study was to evaluate the feasibility of ultrasonic spectroscopy to monitor the changes of mechanical properties (rupture force and modulus of elasticity) and chemical properties (soluble solids content) in two cultivars of persimmons (Karaj and Shomali) during 3 weeks of storage. Samples’ ultrasonic properties such as ultrasonic velocity and attenuation coefficient were analyzed with transducers, and their textural properties were obtained using destructive compression test and their refractometric properties were measured from its fresh-squeezed juice in laboratory. Mechanical and chemical properties were statistically modeled from ultrasonic parameters. The results showed that our proposed model could predict persimmons’ mechanical and chemical properties well, i.e., rupture force (R2 = 0.893/0.837; RMSE = 3.683/3.849 for Shomali and Karaj cultivars, respectively), modulus of elasticity (R2 = 0.826/0.861; RMSE = 0.231/0.217 for Shomali and Karaj cultivars, respectively) and soluble solids content (R2 = 0.931/0.987; RMSE = 0.519/0.851 for Shomali and Karaj cultivars, respectively).

Pattern recognition and genetic algorithms for discrimination of orange juices and reduction of significant components from headspace solid‐phase microextraction

Orange (Citrus sinensis L.) juice comprises a complex mixture of volatile components that are difficult to identify and quantify. Classification and discrimination of the varieties on the basis of the volatile composition could help to guarantee the quality of a juice and to detect possible adulteration of the product. To provide information on the amounts of volatile constituents in fresh-squeezed juices from four orange cultivars and to establish suitable discrimination rules to differentiate orange juices using new chemometric approaches. Fresh juices of four orange cultivars were analysed by headspace solid-phase microextraction (HS-SPME) coupled with GC-MS. Principal component analysis, linear discriminant analysis and heuristic methods, such as neural networks, allowed clustering of the data from HS-SPME analysis while genetic algorithms addressed the problem of data reduction. To check the quality of the results the chemometric techniques were also evaluated on a sample. Thirty volatile compounds were identified by HS-SPME and GC-MS analyses and their relative amounts calculated. Differences in composition of orange juice volatile components were observed. The chosen orange cultivars could be discriminated using neural networks, genetic relocation algorithms and linear discriminant analysis. Genetic algorithms applied to the data were also able to detect the most significant compounds. SPME is a useful technique to investigate orange juice volatile composition and a flexible chemometric approach is able to correctly separate the juices.

Identification of Sulfur Volatiles in Canned Orange Juices Lacking Orange Flavor

The purpose of this study was to understand why some canned orange juices are not perceived as orange juice. Sensory flavor profile data indicated that the primary odor (orthonasal) attributes were tropical fruit/grapefruit, cooked/caramel, musty, and medicine. By comparison fresh-squeezed juice lacked these odor attributes. GC-O analysis found 43 odor-active components in canned juices. Eight of these aroma volatiles were sulfur based. Four of the 12 most intense aroma peaks were sulfur compounds that included methanethiol, 1-p-menth-1-ene-8-thiol, 2-methyl-3-furanthiol, and dimethyl trisulfide. The other most intense odorants included 7-methyl-3-methylene-1,6-octadiene (myrcene), octanal, 2-methoxyphenol (guaiacol), 2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone (homofuraneol), (E)-non-2-enal, (E,E)-deca-2,4-dienal, 4-hydroxy-3-methoxybenzaldehyde (vanillin), and alpha-sinensal. Odorants probably responsible for the undesirable sensory attributes included grapefruit (1-p-menth-1-ene-8-thiol), cooked [2-ethyl-4-hydroxy-5-methyl-3(2H)-furanone, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (Furaneol), and 3-(methylthio)propanal (methional)], musty [7-methyl-3-methylene-1,6-octadiene and (E)-non-2-enal], and medicine (2-methoxyphenol). The canned juices also lacked several aldehydes and esters normally found in fresh orange juice.

A Rapid Liquid Chromatography Electrospray Ionization Mass Spectrometryn Method for Evaluation of Synephrine in Citrus aurantium L. Samples

Immature bitter orange fruit and its extracts have been introduced into the market as an alternative to Ephedra in weight loss products. However, the safety of the immature bitter orange fruit and its extracts is a debated argument due to the presence of synephrine, a constituent known as a sympathomimetic agent. In this paper, we describe the development of a new, rapid, and simple liquid chromatography-electrospray ionization-tandem mass spectrometry method devoted to the quantitative determination of synephrine in bitter orange samples, containing a high quantity of synephrine, and sweet orange samples, known to contain a low level of synephrine but at the same time being one of the main synephrine sources in a normal human diet. Two bitter orange dry extracts containing 5 and 6% sSynephrine and 10 sweet orange samples have been analyzed. Between the sweet orange samples, six were fresh oranges and four were fresh-squeezed juices; in these samples, the synephrine levels ranged from 0.00128 to 0.00349%.

Handling Practices During Distribution of Kinnow-Mandarins (Citrus nobilis x Citrus deliciosa) Used for Preparation of Fresh-Squeezed Juices and their Effects on Microbiological Safety

The objective of this study was to assess the microbiological safety of Kinnow-mandarins (Citrus nobilis X Citrus deliciosa) used for preparation of fresh squeezed juices by street vendors. One hundred and fifty Kinnow mandarin samples were collected from different points in the distribution chain from the same lot, washed and aliquots of the wash samples were analyzed for total aerobes, Staphylococcus, total and fecal coliforms, Salmonella and Shigella. Although, there was no notable increase in the total aerobic, total or fecal coliform counts, total staphylococcal counts increased significantly (P<0.05) during distribution to street vendors; seventy-two samples from the street vendors showed the presence of coagulase positive Staphylococcus aureus, twenty-three of these produced enterotoxins B and C. Salmonella and Shigella were not detected in any of the samples. Sources of high numbers of enterotoxigenic S. aureus were traced to unhygienic manual handling by middle level buyers and by street vendors. The results of our study demonstrate the poor microbiological quality of Kinnow-mandarins, the possible entry points of contaminants in the distribution chain of these fruits and unhygienic vending practices. Appropriate intervention measures are needed to ensure safe fresh squeezed juices for consumers.

QUANTITATIVE STUDY OF FREE SUGARS AND MYO-INOSITOL IN CITRUS JUICES BY HPLC AND A LITERATURE COMPILATION

Three hundred and six (306) commercial samples from 19 processing plants in Florida, composed of frozen concentrated orange juice, orange juice from concentrate, and pasteurized orange juice, were analyzed for their sugars content by HPLC. In addition, the sugar profile of fresh-squeezed juice from 9 different cultivars of sweet oranges, 2 tangors, and 4 tangelos grown in Florida are included. Sucrose, fructose, glucose, total sugars, glucose/fructose ratio, and myo-inositol contents are presented. Mean ± standard deviation sugar levels for 100 mL of frozen concentrated orange juice were 4.1 ± 0.5 g of sucrose, 2.1 ± 0.2 g of fructose, 1.9 ± 0.2 g of glucose, and 0.1 ± 0.1 g of myo-inositol, from juices processed in Florida. A review of the methodology for the detection of sugars by HPLC in citrus products is presented; most results having been acquired by HPLC analysis utilizing NH2 column and acetonitrile/water. A compilation of literature furnishing information on free sugar contents in orange and grapefruit juices by cultivar, and in commercial samples, is also presented.