FIELD OF THE INVENTION

The present invention in all of its associated aspects is directed to a method of processing fruits and vegetables (e.g. pineapples) using minimal thermal parameters and a mechanism to enable accurately defined slice separation and spacing between slices while keeping them intact to facilitate pasteurization.

BACKGROUND OF THE INVENTION Processing food is required for preservation to eliminate pathogens. In particular, fruits and vegetables are perishable and seasonal and thus need to be processed to be microbiologically safe, be shelf stable at ambient conditions for longer period of time and be made available to different parts of the world.

Modem food processing technologies have been developed since the 19 ^th century. dating back to the introduction of hermetic seal ^" through, vacuum bottling process in the 1 800s to serve military needs Since then, different thermal and non-thermal processing techniques have been developed and studied to offer more convenience, quality and are cost effective to manufacturers and consumers.

Thermal processing involves the addition and/or removal of heat such as freeze preservation. Under thermal processing are blanching, pasteurization methods, and heat sterilization methods.

Of particular interest to the present invention is the applicability of basic pasteurization methods on whether we can get the energy to where it needs to be in a food solid (fruit or vegetable) for it to be rendered safely processed. Depending on the geometry of foods and how easily it can be penetrated by energy or heat, a minimum penetration depth is required for heat deposition into all parts of the food. For example, fruits like pineapple is about 85% water. Data on the penetration depth for water shows that energy with wavelengths that have less than 4mm for pure water can achieve only surface heating ^|2'5] . Based from this minimum required penetration depth, practical and regulator}' limits. mid-lR, Far 1R and microwaves with wavelengths 1 mm to l m UV between 10-400nm. IR heating between 750nm-lmm, Near-IR heating. Radio frequency heating and Ionizing radiation (γ radiation ₆ oCo or mCs isotopes) are eliminated ¹ ' ^''7 ' ^{10' 121} . Pasteurization through microwave heating is commercially available and proven and thus may be quite suitable if heating profile is uniform enough.

Other viable/ potentially viable thermal pasteurization methods include the conventional heating via conduction or convection and Ohmic heating. Conventional heating via conduction or convection such as retort heating is the most viable with the largest range of possible implementation. This is also flexible because of possible trade-offs with many variables such as time, temperature, product quality and packaging economics.

With the application of heat comes the inherent disadvantage of loss of original flavor, taste, appearance, color and nutritional qualities. These factors have led to the intensive developments in the application of non-thermal processing technologies to food manufacturing. Examples of non-thermal techniques are the use of pulse electric fields, ultrasound, high pressure processing, irradiation, oscillating magnetic fields and the use of gas such as ozone, carbon dioxide and cold plasma ^{[" 4* 6} ' ^{8' 1 L l'} Based on physics calculations, biological inadequacy or regulatory limits. Microwave cooking. Conventional heating and High Pressure Processing were the most likely options for microbial inactivation. Other means of eliminating bacteria are chemical treatments.

Microwave Heating and High Pressure Processing have the ability to apply pasteurization energy directly to the product but implementation will be limited due to high cost.

Food can also be processed aseptically. Aseptic food processing involves the strict control of sterile operating conditions in processing so as to prevent microbial contamination ¹⁹ This includes a tightly controlled thermal process and filling the sterile product into the sterile package in a sterile environment to produce a shelf stable product ^{[, 4} ' ^1<5] .

This invention relates to an alternative version of the aseptic sterilization process This invention provides more efficient heat transfer to the food material thereby reducing the heat required for pathogen inactivation. Reduction of the thermal processing parameters in this invention will improve product qualit}' while enliancing flexibility in packaging design.

Figure 1. Process Flow Diagram 'ΊΑΤΈ. THIC*

A. Top View

B. Isometric View

FIGURE 2 (A & B) Layout of Slice (or Piece) Carrier SUMMARY OF THE INVENTION

It is the general object of the invention to produce an acceptable alternative and more efficient way of processing fruits and vegetables.

It is a further object of tins invention to employ a means of setting the fruit or vegetable pieces at optimum distances apart during processing for maximum heat transfer efficiency while keeping the fruit or vegetable pieces intact.

It is another object of Oris invention to process fruits and vegetables using minimal thermal processing in aseptic and anaerobic conditions.

It is an additional object of this invention to provide a processing method for an improved product quality and shelf life. This includes but not limited to deactivation of polyphenoloxidase (PPO).

One aspect of the present invention is based on the efficacy of destruction of the food pathogens to ensure food safety. This process is more efficient than conventional food pasteurization such as retort. A pathogenic analysis on the food solid (fruit or vegetable) can theoretically derive tire minimum required time and heating at the coldest spot of the product to ensure, food safety. Considering heat absorption properties and food geometry (e.g. thickness), application of heat preferably direct at the point where it needs to be in the food can minimize the thermal requirement needed for pathogen inactivation. The temperature and time derived will be significantly below- retort processes. Retort processes (canning methods) are limited by thermal diffusion across and inside the package, thus needing longer heat application and the disadvantage of nutritional, flavor and texture loss. Applying directly the heal to all points in the food solid up to the minimum required heating times, can provide improved product quality, accessible product intervention even after sterilization and offer packaging flexibility and design options. This can be viably achieved through the aseptic processing version of conventional heating, which will involve control through separation of food solid pieces (pineapple slices settled at a fixed distance from each other) for greater heat penetration at minimum heatin along with the appropriate thermal and anaerobic S3'Stems and controls. In tins invention, the time and heat needed for a typical food solid immersed in liquid can be determined. Tliis new process significantly reduces changes due to Maillard reactions and improves nutrient and other quality attributes with the lower pasteurization times. hi the preferred embodiment, the food solid pieces are placed into "slice earners" which sets the food pieces apart from each other. This allows for faster heat penetration into the solid, preferably distanced at specified fixed thickness (geometry), thus minimal heal and time needed to achieve pathogenic safety.

Suitable aseptic and anaerobic conditions, including immersion liquid composition, pH, temperature and time of processing, preconditioning, and oxygen concentration are chosen. These conditions are controlled to minimize the physical and chemical changes and sensory attributes of a food solid while allowing efficient penetration of the heat to all points of the- fruit slices.

Another aspect of the present invention is the texture measurement technique of which the improvement in the quality of the fruit or vegetable processed is being measured.

All of the foregoing aspects in all of their associated embodiments that can be described as illustrative within the skill of the relevant art are also included within the true spirit and scope of the present invention. BRIEF DESCRIPTION OF THE DR WINGS

FIGURE 1 is a flow chart illustrating the process of the present invention as it applies to pineapples.

FIGURE 2 is a layout of the slice carrier as a mechanism for efficient heat transfer while keeping fruit slices intact. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to an alternative and more effective method of processing fruits and vegetables by setting fruit pieces such as pineapple slices under anaerobic conditions. In a preferred embodiment, pineapple or pineapple slices are processed aseptically. However, the method of this invention, illustrated by the process of pasteurization of the pineapples, can be generalized to include alternative processes for other fruits and vegetables.

Referring to Figure One, one embodiment of a process incorporates the present invention in which pineapple or pineapple slices are being processed anaerobically and aseptically.

Steps 1 through 8 are done prior to processing outside the anaerobic chamber.

Steps I through 6 are the preparation steps in which the pineapple is being peeled, de- cored and cut into slices at accurate dimensions. The slices are then segregated according to grade and color, hi Step 7 the pineapple slices are packed into a slice holding tube. Then the slices ar e placed at a defined spacing position on the slice carrier. In Step 8, the slices are optionally pre-trealed with firming agents such as calcium ion (e.g. 0.001 -5.00% calcium chloride) and/or sugars and acids. Steps 9 through 19 are the steps where the pineapple slices are processed in the "anaerobic- aseptic ^" chamber, hi Steps 20-22, the empty slice holding tube and slice carrier are removed from the chamber, rinsed, sanitized and recycled to use them again.

Fruit cylinders without core are produced m the steps 1 through 3, after the whole fruit is washed, peeled and de-cored using conventional methods.

Variation in the thickness and diameter of the pineapple slices has an impact on the heating rate and heal distribution in the slice. In step 4, the fruit cylinders are cut into uniform slices. A preferred method of cutting is the use of accurate slicing machines such as water jet cutters or an5 ^; conventional slicers. Cumulative variation in the slice thickness will give significant thermal variation and difficulty to control heat requirement and thus, pathogenic safety. Slice thicknesses could range from 1mm to 40mm, preferably from 8 mm to 25mm. Slice diameter is at the range of 50mm to 120mm, preferably from 70mm to 1 0mm. In Step 5 and 6, end cuts, broken slices and slices with defects are removed. The suitable slices are segregated according to grade and color. In the slice holder, the slices' diameter and thickness must be uniform to ensure uniform heat penetration across all slices. In Step 7, the selected slices are placed into the slice holder tube. The slices on the slice holder are then aligned at defined spacing positions when settled mlo the "slice carrier ^" Figure Two shows the design of the sli ce carrier. This slice carrier not only keeps the slices intact during the process, it also effectively facilitates positioning the slices in the slice holder, facilitating uniform heat distribution.

In Step 8, the settled slices in the slice holder are optionally subjected to a preconditioning step where the slices are immersed in a liquid medium. The liquid medium facilitates sugar, acid, and temperature equilibrium between the slices and tire liquid medium This is also done to wash off or reduce surface polyphenoloxidase (PPO) released alter cutting. The preconditioning solution is a mixture of water-acid or water, acids and sugars, formulated juice, processed juice or fresh juice. The sugars are selected but not limited from the groups consisting of nutritive sugars such as glucose, sucrose, fructose, etc., or from the groups consisting of non-nutritive sugars such as sucralose, trehalose, rieotame, acesulfame-K, aspartame, stevia, etc. or from the groups consisting of pol ols such as maltitol, laclitol, xylitol, sorbitol, etc. Tire sugars are added in the solution in amounts to achieve a °Brix from a range of 8~60°B. preferably from 10 to 22°B. Acidulants are selected but not limited to the groups consisting of organic acids such as citric acid, malic acid, lactic acid, acetic acid, etc. or from the groups consisting of inorganic acids such as phosphoric acid, sulphuric acid, hydrochloric acid, etc. The immersion solutions are acidified and adjusted to keep pH within 2.0 to 4.5, preferably from 3.0 to 3.50. Infusion with calcium ions (e.g. calcium chloride) is also considered for texture modification, added at a concentration ranging from 0.001 -5.0%. preferably from 0.05-1 .5 %.

In Steps 9 and 10, the slices are put inside the airlock chamber where an inert gas such as but not limited to Nitrogen, Argon. Helium, Neon etc. and air inert gas-hydrogen mix (e.g. Nitrogen-Hydrogen, N ₂ /H ₂ ) are purged in cycles of inert gas- vacuum-gas mix cycles to deaerate the chamber. Oxygen must be removed because it interferes with the process and affects the product color and quality. The inert gas (e.g. Nitrogen gas) is purged in the airlock chamber in sequential steps of vacuum, purging, and repeated in a range of 1 to 20 cycles and at a pressure range of 50mbar to 2000mbar. Tins is followed by another vacuum cycle then, the purging of the inert gas-H ₂ mix (e.g. N ₂ /H ₂ ), which could be repealed in a range of 1 to 20 cycles and at a pressure range of 50mbar to 2000mbar. The inert gas-H ₂ mix are in the ratio of 20-99% nitrogen and 1 -5% hydrogen, preferably at 95%N ₂ /5%H ₂ gas mix ratio. There is a possible introduction of oxygen in the chamber which is potentially removed out of the chamber atmosphere through oxygen scrubbers (e.g. H ₂ /N ₂ gas mix, fanbox with catalyst such as palladium catalyst). The oxygen scrubbers and gas analyzers for monitoring of gas are pari of the process gas handling system (Steps 11 , 14) to maintain anaerobic conditions.

In Step 12, the slices are immersed in a heating bath to pasteurize the fruit. The heating bath is formulated to a ^<J Bnx and pH similar to pineapples' "Brix and pH (isotonic solution). The healing solution is a mixture of but not limited towater, acids, sugars, juices, singly or in combination thereof. The sugars are selected but not limited from the groups of nutritive sugars such as glucose, and sucrose, or from the non-nutritive sugars such as sucralose, trehalose, aspartame, stevia, etc. or from polyols such as maltitol, lactitol, xylitol, sorbitol, etc. The heating solution is kept at a "Bri ranging from 8-60°Brix. preferably from 10 to 22"Bnx. The immersion solutions are acidified and adjusted to keep pH within 2.0 to 6.0, preferably from 3.0 to 4.0. Acidulants are selected but not limited to the groups consisting of organic acids such as citric acid, malic acid, etc. or from the inorganic acids group such as phosphoric acid, sulphuric acid, etc. hi the heating step, the temperature of the immersion liquid is controlled to maintain the pasteurization of the product. The temperature range for the heating step is 50°C to 95°C, preferably at 70°C-90°C. The slices may be immersed in the heating solution for about 0.5-30 minutes, preferably 2-20 minutes until the adequate pasteurization temperature is achieved at all points in the pineapple slice, Step 15 involves the addition of antioxidants or aniibrowning agents to improve color and flavor of the product. Polyphenoloxidase (PPO) enzymes inherent m foods are not destroyed with the minimum thermal process. Thus, a preferred method of inhibiting PPO enzymes is through the addition of PPO inhibitors (antioxidants) while keeping the chamber oxygen concentration to less than 0, 1 % 0 ₂ . Antioxidants are selected but not limited from the groups consisting of ascorbic acid, tocopherols, alpha-tocopherol, ascorbyl palmitate, Butyl aled Flydroxyanisole (BHA), sodium ascorbate, Sodium erythorbate, Tertian' b u tylh y dro q uinone (TBHQ), or singly or in combination thereof.

At tins step, flavor adjustments may be done through addition of flavorings, fresh juices or processed juices, acidulants. and sweeteners and/or in combination thereof. The sugars are selected but not limited from the groups of consisting of nutriti ve sugars such as glucose, of non-nutritive sugars such as sucralose, or from the groups consisting of polyols such as maltitol, etc. Acidulants are selected but not limited to the groups consisting of organic acids or from the groups consisting of inorganic acids. Step 16, after the slices are heated, they are immersed in a cooling solution with temperature set at a range of 4-30°C preferably kept below 10°C. The cooling step is done for about 0.50 to 30 minutes preferably 3-5 minutes. Same as in the heating step, the cooling mixture is formulated in consideration to the pineapples' "Bri and pH, preferably 10-22°Brix and pH of 3.0-4.0 respectively. Components of the preconditioning, heating and cooling solutions could be but is not limited to water, singly or in combination with sugars, acidifiers, juices, antioxidants, flavors, coloring materials, stabilizers, preservatives, nutrient forti i cants, processing aides and firming agents. Antioxidants are selected but not limited from the groups consisting of ascorbic acid, tocopherols, alpha-tocopherol, BHA, sodium ascorbate, Sodium erythorbate, or combination thereof Colors are selected but not limited from the group consisting of natural colorants such as caramel color, and annatto color, or from the groups consisting of artificial colors such as FD&C Red #40, and FD&C Red #3, singlv or in combinations thereof

Flavorings are selected but not limited from the groups of natural and artificial flavors such as but not limited to mango flavor, peach flavor, and passionfruit flavor, singly or in combinations thereof.

Preservatives are selected but is not limited from the group consisting of natural preservatives such as sugar, acid foods such as lemon and vinegar, tocopherols, rosemary extracts, sugar, salts, oils, spices or from artificial preservatives such as but not limited to ascorbic acids and its potassium, calcium and sodium salts, citric acids, benzoales. nitrites, sorbales, metabisulfites, sulfates, sulfites, BHT, BHA, singly or in combinations thereof.

The solutions can further comprise of food grade additives such as stabilizers, nutrient fortifi cants such as vitamins and minera!s, and processing aids such as defoamers, clarifying agents, cata sts, flocculating agents, enzymes, coagulants and finning agents.

Steps 13 and 17 describe the process recycling and regenerating of the immersion solutions to maintain its isotonic characteristics with pineapple.

In Step 18 and 19. describes the un- mounting of the slices while on the slice holder. The slices are then places on the ' ^" slice carrier", packed in sterilized packages and sealed inside the chamber.

The resulting product is a minimal!}' processed and pasteurized fruit such as pineapple slices that is closer to the quality of the fresh compared to tire current retorted pineapple products. A sample evaluation of the sensorial attributes of the slices processed using the present invention is compared to the fresh fruit and current canned products. Control of sensor}" attributes is being measured through color, texture and flavor.

Texture profile analyses shown in Figures 4 (a-e) represent the actions of the motions of the jaw to bite size pieces of food. The texture measurements which give force- time-distance curves, characterize the food samples in a way that best represent how humans perceived the food. Using a Brooldleld CT3 Texture analyzer, the food sample (e.g. pineapple) cut into a standard size and shape, is subj ected to controlled compression forces by a compression plale (or probe) just like the action of the teeth in chewing food. The resulting curves are presented with units of load in grams (y- axis) as the resistance of tire material to the compression forces and distance in millimetres (x-axis) as the distance travelled by the probe into the food sample at a set test speed. The test speed used for compression is the 'fast speed ^" at l Omm/s which is the closest parameter speed to the 'jaw speed' or the speed of chewing. Optimization of compression measurements in pineapples was done to determine

onset of texture change at various temperatures and at various times. A set

temperature from 30°C to 70°C (Figures 4. a-e) showed that onset of texture change

was detected at set Temperature ~ 57"C at 5. 10 and 15 minutes. At more than 50°

there is ahead)- a change in the texture of the slices as shown in Figure 4 (d). This

figure also imply that at temperatures exceeding this identified temperature, more

physical and chemical changes happen, thus the fruit is subjected to more damage. ω tiOOu

E

ro

«-> Pineapple Heated & 30 ^" 5r»ins Pineapple Heated @ 30"C 15mins

Distance travel led by the compression probe into the sample, in millimeters

Figure 4 (a). Texture profile showing the resistance to compression force of the fruit

material (Pineapple) heated at a set temperature of 30"C in 5. 10 and 35 minutes.

Texture is measured iu force-distance curve using a Brookfield CT3 Texture

Analyzer set at a lest speed of ] 0mm/s

Pineapple Heated @ 40 ^' C, ISmins

Distance travelled by the compression probe into the sample, in millimeters

Figure 4 (b). Texture profile showing the resistance to compression force of

the fruit material (Pineapple) heated at a set temperatui ^' e of 40°C in 5, 10 and

15 minutes. Texture is measured 111 force-distance curve using a Brookfield

CT3 Texture Analyzer set at a test speed of lOmm/s lOOOO

E

ro

u>

Pineapple Heated @ 50 ^' C, 15mins

Distance travelled by the compression probe into the sample, in millimeters

Figure 4 (c). Texture profile showing the resistance lo compression force of

the fruit material (Pineapple) healed at a set temperature of 50°C in 5 10 and

15 minutes. Texture is measured in force-distance curve using a Brookfield

CT3 Texture Analyzer set at a test speed of l Omm/s Pineapple Heated @ 60 ^:' C, lBmins

Distance travelled by the compression probe into the sample, in millimeters

Figure 4 (d). Texture profile showing the resistance to compression force of the

fruit material (Pineapple) heated al a set temperature of 60°C in 5, 10 and 15

minutes. Texture is measured in force-distance curve using a Brookfield CT3

Texture Analyzer set at a test speed of l Omm/s. Onset or start of texture change

was observed at a measured temperature of 57°C.

w 70U0

E

ro

Pinsapple Heated φ 70 5mi

—»» Pineapple Heated @ 70° C, 15mins

Distance travelled by the compression probe into the sample, in millimeters

Figure 4 (e). Texture profile showing the resistance to compression force of the

fruit material (Pineapple) heated at a set temperature of 70°C in 5, 10 and 15

minutes. Texture is measured in force-distance curve using a Brookfield CT3

Texture Analyzer set at a test speed of lOmm s Another representation. Figure 5, shows the comparison of the texture profile of the fresh fruit, the canned fruit and the processed fruit using the present invention set at high, medium and Sow temperatures of 95 ^D C, 85°C and 72°C respective!)'. Texture is measured using a texture analyzer operated in a compression mode, hi compression mode, the probe comes in contact with the fruit sample at a set distance at a set speed. The texture pro file is shown in terms of the load (in grams) as a function of time and distance. If the texture profile curve is more inclined to the left, there is a faster detection of resistance as pressure is applied (compression). In this case, the fresh pineapple slice has the fastest rising curve; indicating measurement of resistance at the surface thus a firmer material is being measured. From the graph (Figure 5), the texture effect of the new process (present invention) set at high, medium and low temperature processed at the minimal times, is closer lo the fresh and firmer than the canned product, thus of better lexture.

10000

Canned Pineapple Avg

D

Distance travelled by the compression probe into the sample, in millimeters

Figure 5. Temperature and Texture profiling comparison of fresh fruit, canned

fruit and processed fruit using the present invention at High temp (95°C),

Medium temp (85°C) & Low temp (72°C). Ln Figure5, the texture profile of the pineapples processed using the present invention is closer to the fresh in terms of slope when compared to the canned pineapple. The more the curves are leaning closer to the left, the detection of the resistance to the compression force is faster and higher, thus the firmer is the material. As shown in Figure 5, texture curve for fresh pineapple is closer to the left, followed by pineapple processed using the present invention at different temperatures. Canned pineapple is the farthest from the left, thus of the lowest quality.

The load (g) at the highest peak per curve is the firmness delected. The highest load is measured for the high temperature process (95"C) of the present invention as shown by Figure 5. At high temperature processing (95"C), there is more vacuole damage in the fruit, and more leaking of juice into the fruits previously air-filled spaces. Liquid is harder to compress than gas thus a higher load needed for compression. Canned pineapple slices have longer processing parameters, the fruit is more damaged, thus its texture curve as shown in Figure 5 shows a lower slope and a lower peak signifying less quality. so.o ® Av rnp.c F esh

i Cu em Retort

-S 65.0

<>

S 60.0 _Λ

A v erope <3nn

[ C u i r cn l Retort Pro es

45.0

4 6 S 10

Sl ic e- n um s"

Chart 6. a Comparison of ^* L color values of P rocesed Pineapple vs

F res h a nd Canned

Ln terms of color, the *L, *a, ^:|: b values in Charts 6.a-d show a comparison of the color measurements among fresh, canned and the new process. *L values refers to the lightness or darl iess of a sample. From Figure 6. a, even at a high temperature process of 95°C, the *L values of the new process is better than canned pineapple. (i <i ^j ' ed

'J 5.0

^■ 4.0 -.1.11 1.0 0 1

tolot vain

Chart 6.b Comparison «I ^* l X. ^" ii color values, of Proce

Pineapple vs Flesh and Cnnned

*a color values refer lo the redness-greeness and yellowness-blueness of a sample. Figures 6.b shows that *a and *b color values for canned pineapple are not significantly different from the pineapple processed using the new invention.

(Current Retort

t i Cannr.

50.0 (Current Retort

Process*

4 .0

0.0 1 .0 30.0

^; b olo

oinparison of *L & "b color values of Pro esed Fin iipp!-e

vs Fresh and Canned Taking the averages of the one day ^:|! L color change of the processed pineapples against the fresh. Figure 6.d shows that processing pineapples using the new invention shows belter color quality than canned, even at high temperature of 95°C.

-20.0 -Jt S .O -10.0 - 5.0 0.0

A erag e Colo r C ha ng e m Δ Ι.

Cha rt 6.d Com parison of Average A ' L Color values of Processed

Pineapples f rom F resh The pineapple produced from tliis invention is compared with the retorted canned pineapple. The quality of the retorted fruit and its sensory properties, in terms of color, taste and texture, were inferior compai ^' ed to the quality of the fruit processed through this invention. Table 1 shows the results of an initial experiment to verify whether a reduction in pineapple processing conditions will lead to observable benefits in quality versus the conventional retort treatment. Evaluation of the fruit is characterize in terms of taste, texture, and color response of the pmeapple to reduced processing conditions.

Table 1. Taste characterization table of pineapple processed using cun enl invention versus Fresh and Canned pineapple (control)

*Outlier, error may be due to variation in pineapple material

It is noted from Table 1 that there is a generous room within the bold line which can be still considered "as good as fresh" mostly at tire 80°C and 85°C from 240 to 270 seconds. Furthermore, it is also noted that even the highest processed products, heated at 90°C and 95°C, taste better than the canned pineapple (control). Generally, fresh pineapple is superior in flavor over a processed pineapple and thus, a reduced processing time generally favors improvement to taste profile.

2

Table 2. Texture characterization table of pineapple processed using current invention versus Fresh and Canned pineapple (control)

From Table 2 for texture, fresh pineapple has the characteristic "bite ^" and crunchiness, while the control pineapple will be noticeably softer and soggier. Looking at lower processing temperature and times, at 80°C and 85°C, we note an area williin the bold line that still corresponds to a fresh-like texture, while in 90°C and 95°C, there are no responses that indicate fresh-like texture.

Table 3. Color characterization table of pineapple processed using current invention versus Fresh and Canned pineapple (control)

Table 3 reports the color response evaluation to van ⁿ ing processing conditions. While there are no samples produced in the 90°C and 95°C processing that is similar to the fresh pineapple, there are samples for the 8U°C and 85°C that are sufficiently processed are still identical to a fresh pineapple in terms of color. As tire processing conditions are increased, color of processed pineapple becomes comparable to canned pmeapple (control). It is noted that at lower temperature of 80°C even at 360 seconds, color of samples are still identical to the fresh than from the canned pineapple.

Overall, fresh pineapple is superior in terms of color, flavor and texture over a processed pineapple but a reduced processing temperature and time provides improvement on quality and sensor) ⁷ attributes. The following examples describe the process of the invention with pineapple.

EXAMPLE 1.

1. Three kilograms of sugar is dissolved in fi ve gallons of distilled ater for both heating and cooling solutions. Malic acid is added at 0.5g per gallon of water to acidify the solutions and adjusted to keep pH within 3.0 to 3.5. The immersion solutions are conveyed in a continuous thermal heating bath, pasteurized and asepticaliy transferred into the aseptic-anaerobic chamber. Pasteurized immersion solutions are filled into the water bath and hea ed or cooled to the set temperature. For the heating bath, temperature is set at 73-78 degrees Celsius. The cooling bath is set at 4-J O degrees Celsius. Ten to fifteen previously peeled and de-cored pineapple cylinders are cut into slices using a w¾!er jet cutter or any other conventional cutters. S lice Llnckness is a primary parameter for the desired heating profile thus an accurate sheer is prefeired. Pineapple slices are cut at a thickness in a range from 8-25 mm. End cuts, defects (e.g. eyes, brown spots, blemishes). broken slices, very pale slices, off centred inner cores, mashed pieces are removed. Selected slices are segregated according to color and grade. The batch of 10 slices are packed into a slice holding tube, aligned and settled into the ''slice carrier ^" .

The settled slices are then passed into a preconditioning solution wliich is composed of fresh pineapple juice with added acid(s) such as citric acid (e.g.

0.001 -10.00% citric acid) for pH adjustments preferably at pH from 3.0 to 3.5. The ' slice carrier ^" is then inserted into the vacuum airlock of the anaerobic chamber where an inert gas such as Nitrogen and inert gas-hydrogen gas mix are purged. The airlock is set to 1 to 5 cycles of vacuum for 120 seconds and at a pressure range of 300mbar to l OOOmbar. Nitrogen purging for 45 seconds, then followed by purging of gas mix (e. g. 5 ⁽⁾ -99.998%N ₂ /l -5%H ₂ ). The airlock is then opened from the inside chamber and the "slice carrier ^" is pulled out. The water bath is then set to flow using mechanically operated paddles. The settled slices are then immersed into the healing bath at a set temperature of 70-9( ⁾ °C for 2-10 minutes. The slices are then taken out of the healing bath and submerged directly to a flowing cooling water bath kept at a temperature range of 5-17°C for about 3- 5 minutes. The slices are then removed from the "slice carrier ^" , packed and sealed in sterilized packages under aseptic and anaerobic conditions.

EXAMPLE 2.

Six kilos of trehalose is mixed in five gallons of distilled w ater each for the preconditioning, heating and cooling baths. Citric acid is added to acidify the solutions and adjusted to keep pH within 3.0 to 3.5. The preconditioning mixtur e is optionally added with a solution of ] % of calcium chloride. The heating and cooling mixtures are pasteurized and aseptically transferred into the aseptic- anaerobic chamber. Pasteurized immersion sol utions are filled into the water bath and heated or cooled to the set temperature. For the heating bath, temperature is set at 73-78 degrees Celsius. The cooling bath is set at 4-10 degrees Celsius.

Ten to fifteen previously peeled and de-cored pineapple cylinders are cut into slices using a conventional fruit sheer. The fruit slicer is designed to produce slices with fixed thickness. Slice thickness is a primary parameter for the desired heating profile thus an accurate slicer is preferred. Pineapple slices are cut at a thickness of 8-15 mm. End cuts, defects (e.g. eyes, brown spots, blemishes), broken slices, very pale slices, off centred inner cores, mashed pieces ar e removed from the tests. The chosen slices are segregated according to color and grade. For example purposes, light yellow good quality (fancy grade) slices are chosen and segregated into 10 slices per batch. Color readings may be taken 8 times per slice (4 times on each side of the slice) using a portable colorimeter. One batch may be subjected to a texture analyzer for texture readings, where a rectangular ^' strip is taken out of each slice and analyzed for texture. Excess slices may be blended and analyzed for Brix, pH. acidity and vitamin C content. The results of these analyses may be compared to the processed slices.

The batch of 10 slices are packed into a slice holding tube, aligned and settled into the "slice carrier". The slices are then optionally immersed into the preconditioning solution for about 3-5 minutes. Tire carrier with the slices is then inserted into the vacuum airlock of the anaerobic chamber. The airlock is slightly opened and Nitrogen gas is purged in for about 1 to 10 minutes. The airlock is then closed from the outside. The airlock is then opened from the inside chamber and the ''slice carrier ^" is pulled out. The water balh is then set to flow using mechanically operated paddles. The settled slices are then immersed into the heating bath at a set temperature of 73-78"C for 3-5 minutes. The slices are then taken out of the heating bath and submerged directly to an ' agitating ^' cooling water balh for about

3-5 minutes. The slices are then removed from the "slice carrier ^" , packed and sealed in sterilized packages under aseptic and anaerobic conditions.