Raw Apple Juice Research Articles

The effects of different technologies on Alicyclobacillus acidoterrestris during apple juice production

In this study, the effects of various processing steps applied during apple juice processing on Alicyclobacillus acidoterrestris were investigated. Raw apple juice was inoculated with A. acidoterrestris spores at two inoculum levels of 1×103 cfu/ml and 1×106 cfu/ml. Following enzymatic treatment, the raw juice was processed into clear juice using either conventional clarification or ultrafiltration. The number of A. acidoterrestris spores in the final product was determined to be dependent on both initial contamination level and processing conditions. Increasing temperature to 50 °C during depectinization resulted in a higher spore counts at both inoculum levels. Even if the ultrafiltration process was found to be much more convenient for the retention of A. acidoterrestris when compared to conventional clarification, the spores could penetrate the ultrafiltration membranes having both 20 and 50 kDa. Increasing membrane pore size and initial spore counts in the feed solution also increased the number of spores penetrating the membrane during ultrafiltration.

INFLUENCE OF CONVENTIONAL CLARIFICATION AND ULTRAFILTRATION ON THE PHENOLIC COMPOSITION OF GOLDEN DELICIOUS APPLE JUICE

Abstract The effects of conventional clarification and ultrafiltration techniques on the phenolic composition of apple juice was studied. Since the health benefit of fruits and fruit juices have been ascribed, in part, to the phenolic antioxidants, it is very important to know what the effects of processing steps are on the level of phenolic compounds in fruit juices. The total losses of phenolic compounds were determined to be 28% and 7% during conventional clarification using gelatin and bentonite, and ultrafiltration, respectively. A total of 14 phenolic compounds were identified in apple juice prepared from Golden Delicious apples. The phenolic compounds were found to be based mainly on hydroxycinnamic acids (∼ 50% of total phenolics) and chlorogenic acid was found to be the major phenolic compound with its concentration as high as 465.45 mg 1−1 in raw apple juice.

Flow-injection chemiluminescence determination of epinephrine in pharmaceutical preparations using raw apple juice as enzyme source

Raw apple juice exhibits the activity of polyphenol oxidase which can be employed for the determination of mono-, di- and polyhydric phenols. The chemiluminescence detection in the two-channel manifold was used to develop the new procedure for determination of epinephrine. Epinephrine can be determined by this method in pharmaceutical preparations in concentration ranges 1.0–10.0 and 10.0–25.0 mg l −1, with a detection limit of 0.2 mg l −1. Good selectivity against typical antioxidants and other coexisting substances was achieved. Relatively slow loss of the enzyme activity was observed during 1 week. The proposed method is very simple. Fresh juice solution from one apple can be prepared in 10 min and used for at least 8 h with excellent precision. Consumption of luminol solution was 0.15 ml min −1. The throughput was 20 samples per hour.

A new integrated membrane process for producing clarified apple juice and apple juice aroma concentrate

An integrated membrane process for producing apple juice and apple juice aroma concentrates is proposed. The process involves the following operations: an integrated membrane reactor to clarify the raw juice; reverse osmosis (RO) to preconcentrate the juice up to 25°Brix; pervaporation (PV) to recover and concentrate aroma compounds, and a final evaporation step to concentrate apple juice up to 72°Brix. These operations were tested in laboratory and pilot plant units. Promising results were obtained with the membrane operations involved. In order to have an economic process assessment, the pilot plant units were assembled into an integrated unit and operated with raw apple juice. The products were more clear and brilliant than apple juice produced by conventional methods. The integrated membrane process also seemed to be more advantageous on the basis of economics than the conventional one.

Microfiltration of apple juice using inorganic membranes: Process optimization and juice stability

AbstractCrossflow membrane microfiltration of low‐pectine raw apple juice was studied using inorganic membranes (TECH SEP Carbosep®, Lyon, France) having a nominal pore size of 0.2 μm. Permeate flux was measured at different operation conditions (trans‐membrane pressure between 100 and 500 kPa, feed velocities between 1 and 6 m/s, and temperatures of 293, 298 and 323 K). Some concentration experiments were made in order to study the rejection of pectins and polyphenols at different VCR (volume concentration ratio) values. Final stabilization tests were carried out to analyze the long‐term clarified juice behaviour.

Inhibition of Enzymatic Browning in Fresh Fruit and Vegetable Juices by Soluble and Insoluble Forms of β-Cyclodextrin Alone or in Combination with Phosphates

Soluble and insoluble forms of β-cyclodextrin (β-CD) can be used to inhibit enzymatic browning of fresh raw apple, pear, white grape, and celery juice. The anti-browning effects of soluble CDs were concentration-dependent. Concentrations (1−1.5% w/v) of soluble (un-derivatized, hydroxyethyl, or maltosyl) β-CD substantially inhibited browning of Granny Smith apple juice held at room temperature for several hours while untreated juice browned in minutes. Higher concentrations (4−10%) of soluble β-CD derivatives completely inhibited the browning of apple juice held for 1 day under these conditions. The effectiveness of β-CD was greatly enhanced by the presence of phosphate-containing compounds. Hence, only 1% levels of soluble β-CD (in the presence of 0.25−0.5% phosphate compound) completely inhibited browning in apple juice held for 1 day at room temperature or for up to 2−3 weeks at 4 °C. Treatment of apple, pear, white grape, and celery juice with an insoluble form of β-CD, either in a batchwise or flow-through process, resulted in juices free of CDs that resisted browning indefinitely. Keywords: Enzymatic browning; inhibition; cyclodextrins; vegetable and fruit juice; phosphates; phytic acid

Oxalic Acid in Commercial Pectins Inhibits Browning of Raw Apple Juice

Various commercial pectin preparations were tested for their ability to prevent enzymatic browning of fresh, raw, Granny Smith apple juice. Six of eight commercial pectin samples inhibited browning to some degree, and two of the pectin preparations completely prevented fresh, unrefrigerated, apple juice from browning for 24 h when added to juice at a concentration of 0.5% (w/v). Fractionation and testing of one pectin preparation showed that the antibrowning activity was not due to pectin, per se, but to the presence of low levels of oxalic acid (<0.5%) in the pectin preparations. When oxalic acid was removed from the commercial pectins, antibrowning activity was lost or greatly reduced. Pure oxalic acid was also found to inhibit browning reactions in fresh juice. Pure oxalic acid is not an approved food additive, but it does occur naturally in fruits and vegetables such as rhubarb and spinach

Scaling up pulsatile filtration flow methods to a pilot apparatus equipped with mineral membranes

This paper addresses the problem of extrapolating the technique used for filtration enhancement by superimposing pressure and flow pulsations to a pilot model of an actual production unit equipped with 14 Carbosep mineral membranes. The experimental results obtained with raw apple juice show that the maximum permeate flux enhancement is obtained at a frequency of 1 Hz and a pulsed volume of 200 ml which is significantly less than the internal volume of the membranes. The flux enhancement is a linear function of the ratio of pulsatile to steady flow and can reach up to 140% when the circuit settings are unchanged. However, when the time-averaged mean transmembrane pressure is conserved the flux enhancement is much smaller and barely exceeds 25%.

Microfiltration and Ultrafiltration Comparison for Apple Juice Clarification

ABSTRACTUnpasteurized raw apple juice processed by microfiltration (MF) or ultrafiltration (UF) was evaluated for quality and the methods compared for process efficiency. Juice permeate was analyzed for total solids, soluble solids, color, turbidity, pH and acidity. Apple juice processed by MF was significantly (p &lt; 0.05) darker, more turbid, contained higher total and soluble solids than juice processed with UF, and was preferred by a taste panel. MF processed more permeate per unit time than UF under similar operating conditions with no noticeable difference in power consumption (watt‐hr/L).

Control of Enzymatic Browning in Apple with Ascorbic Acid Derivatives, Polyphenol Oxidase Inhibitors, and Complexing Agents

ABSTRACTNovel browning inhibitors were evaluated in raw apple juice and on the cut surface of apple plugs, using quantitative measurements of color changes during storage to assess treatment effectiveness. Ascorbic acid‐2‐phosphate (AAP) and ‐triphosphate (AATP) showed promise for cut surfaces but were ineffective in juice. Ascorbic acid‐6‐fatty acid esters showed anti‐browning activity in juice. Cinnamate and benzoate inhibited browning in juice but induced browning when applied to cut surfaces. Combinations of β‐cyclodextrin with ascorbic acid (AA), AAP or ascorbyl palmitate were effective in juice but not on cut surfaces. Combinations of AA with an acidic polyphosphate were highly effective with both juice and cut surfaces.

Comparison of Erythorbic and Ascorbic Acids as Inhibitors of Enzymatic Browning in Apple

ABSTRACTThe effectiveness of ascorbic acid (AA) and erythorbic acid (EA) in inhibiting enzymatic browning at cut surfaces of apple and in raw apple juice was determined by tristimulus calorimetry. Red Delicious and Winesap plugs, dipped for 90 set in 0.8–1.6% solutions of AA or EA, showed longer lags before the onset of browning with the former compound. AA and EA were similar in effectiveness in apple juice. Because the relative effectiveness of AA and EA depends on the system in which they are compared, they should not be used interchangeably as sulfite alternatives without experimental verification of equivalence.