however , due to their short shelf life , processing into preserved products becomes essential .
fruit juices and beverages are one such processed product which is convenient to use and also help meet the daily requirement of fruits and vegetables in the diet .
healthy beverages , particularly those that offer functional ingredients such as botanicals , minerals , and antioxidants , are increasing in demand . new product introductions in the health drink and fruit juice categories were found to reach over 700 new offerings in year 2003 , up 40% over 2002 .
fruit based functional beverages with refreshing flavors and tastes are being preferred over aerated drinks by the health - conscious consumers , in particular .
nutraceuticals from botanical origin have a great scope to offer varied health benefits such as improved antioxidant profile and protection against various chronic metabolic diseases .
india was reported to be the largest papaya producer ( 2.7  mt ) in the world in 2008 .
apart from its luscious taste and attractive color , papaya is a rich source of antioxidant nutrients such as carotenoids , vitamins c and e , and flavonoids ; the b vitamins , folate , and pantothenic acid ; and the minerals , potassium , magnesium ; and fiber .
together , these nutrients are known to promote the health of the cardiovascular system and protect against colon cancer .
hence , for the present study , papaya was selected for preparation of functional fruit beverage . as the nutraceutical ingredient , aloe vera ( aloe barbadensis miller ) gel was selected .
it is also being studied widely in recent years as a valuable ingredient in foods .
the aloe gel is transparent slippery mucilage containing bioactive polysaccharides , mainly partially acetylated glucomannans .
new products combining the unpalatable aloe gel juice with other health foods particularly antioxidant rich fruits such as berries , peaches , and their extracts has been produced . its blend with tropical fruits such as papaya , however , remains to be explored .
spices are another group of botanicals that are being increasingly used for preparing appetizer drinks and also as an aid to mask undesirable flavor in beverages .
spices are also well known for their antimicrobial and antioxidant activities [ 7 , 8 ] as well as for their therapeutic value [ 9 , 10 ] . a combination of above two botanicals with papaya is proposed to result in a functional beverage with enhanced nutritional and nutraceutical value . with the above facts in view , in the present study , a spiced aloe gel - papaya blend functional beverage was developed and its physicochemical characteristics , antioxidant potential , microbial quality , and sensory acceptability were evaluated . the shelf life quality on storage for five months was also studied .
uniformly ripened papaya of uniform size and shape was purchased from the local market of anantapur .
food grade citric acid , sugar , salt , and other spices were procured in one lot from the local market .
papaya fruits were thoroughly washed under running tap water , peeled , and cut into small pieces .
the pieces were finely blended to obtain papaya pulp , which was filtered through a muslin cloth .
sugar syrup ( 20% ) was prepared and blended with 15% of the obtained papaya pulp .
spice extract was prepared by boiling aniseed , ginger , and pepper in water for few minutes .
citric acid was also added at 0.1% level to achieve the desired acidity level recommended for beverages .
the resultant spiced papaya rts beverage ( spb ) was again blended and heated for a few minutes in low flame .
the spb was then hot - filled into presterilized glass bottles , screw capped , and pasteurized for about 15 minutes at 8090c followed by immediate cooling .
the fresh green aloe vera leaf was taken for the extraction of aloe gel juice .
the gel was washed 3 - 4 times in distilled water , hand crushed , blended , and filtered through muslin cloth .
similar procedure was followed for the preparation of spiced aloe gel - papaya blend beverage ( sagpb ) as spb , except that in sagpb , aloe gel juice obtained was added at different levels of 10% , 20% , and 30% to prepare 10 sagpb , 20 sagpb , and 30 sagpb , respectively .
this was followed by addition of other ingredients , hot filling , pasteurization , cooling , and storage .
the developed beverages were initially evaluated for sensory acceptability in terms of color , flavor , taste , consistency , and overall acceptability . the aloe gel enriched beverage found best in terms of the above mentioned parameters was selected for further storage analysis , along with the control beverage spb .
the selected beverages were stored at room temperature ( 28  2c ) in dark up to five months .
analysis for various parameters was carried out on 0  d and after 45  d , 90  d , 120  d , and 150  d of storage .
the beverage was evaluated for physicochemical characteristics , phytochemicals , and microbial and sensory quality .
the ph of the samples was read with a calibrated ph meter ( elico india l1 - 120 model ) .
titratable acidity was measured using 0.1  n naoh and expressed as percentage citric acid ; total soluble solids ( in brix ) determined using digital hand refractometer ( atago , japan ) and nonenzymatic browning ( neb ) estimated by measuring optical density ( od ) at 440  nm .
total and reducing sugars were determined by the lane and eynon method using fehling 's reagent .
for the estimation of color , test sample was filled in a 3 inch diameter petri dish .
the color was measured using a color reader ( konica minolta cr-10 ) and expressed as hunter l a b units .
l indicates luminosity or brightness , a corresponds to greenness ( )/redness ( + ) , and b corresponds to blueness ( )/yellowness ( + ) .
a direct colorimetric method as given by ranganna   was used for the estimation of vitamin c content .
methanol extractions of fresh samples were carried out using a modified method of banerjee et al . .
aluminium chloride method   was used for determination of flavonoids and the content expressed as mg quercetin equivalents ( qe ) in 100  ml of beverage .
total polyphenols were determined using folin - ciocalteu procedure   and the total phenolic content was expressed as gallic acid equivalents in milligrams per 100  ml of beverage .
total bacterial count ( tbc ) and yeast and mold counts ( ymc ) of the samples were determined by standard plate count method and expressed as log cfu ml .
the sensory acceptability of the samples was evaluated by a group of 20 untrained female panel members between 18 and 40 years of age , selected from the authors ' university .
the samples were randomly coded and served at 15c in 50  ml aliquots to the panelists , along with plain water .
they were asked to rate the samples for various sensory attributes , namely , color , flavor , taste , consistency , and overall acceptability , on a 5-point hedonic rating scale with 5 and 1 indicating the highest and lowest scores , respectively .
the samples were evaluated at the end of each storage interval and the mean scores were reported .
data obtained for the various parameters were expressed as mean values  standard deviations of at least three replications .
statistical analyses were performed using spss ( statistical software student version 16.0 , chicago , il , usa ) .
statistical difference between the means was determined using duncan 's multiple range test ( dmrt ) with the confidence limits set at p < 0.05 ( 95% ) .
papaya fruit and fresh aloe gel juice used in the present study were first characterized for few important parameters .
papaya pulp was found to have moisture content of 86.5% and tss of 15  brix .
aloe gel recorded a higher moisture content of 98.9% and low tss of 0.08  brix .
acidity of papaya pulp was also higher ( 0.33% ) compared to aloe gel ( 0.05% ) . a higher value of nonenzymatic browning was recorded in aloe gel ( 0.09 ) , whereas , that of papaya pulp was found to be 0.04 .
papaya pulp was found to contain a good amount of vitamin c ( 46  mg/100  g ) . for aloe gel
papaya pulp recorded 24.7  mg/100  g , 9.9  mg/100  g , and 14.8  mg/100  g of total sugars , reducing sugars , and nonreducing sugars , respectively , and the corresponding values for aloe gel were 1.85 , 0.03 , and 1.82 , respectively .
the various beverage blends of aloe gel and papaya formulated were initially evaluated for sensory acceptability ( table 1 ) . with regard to color ,
similarly , in terms of taste and flavor , 30 sagpb recorded significantly higher scores compared to control .
the lower score for control sample could be due to its predominantly sweet taste which was not well appreciated by the panelists when given in the generally consumed portion size ( 150  ml ) .
a more balanced taste was witnessed in the ag enriched samples , which was found to increase with increase in percentage of ag .
slightly lower scores obtained for ag enriched samples for consistency could be due to its comparatively thinner consistency compared to control .
the overall acceptability scores indicated 20 sagpb and 30 sagpb to be highly acceptable with scores of 4.64 and 4.71 , respectively , significantly higher than 10 sagpb and control .
a major problem with commercial aloe gel juice and beverages is adverse / bitter taste , which could be successfully avoided in the present study with suitable processing operation , with addition of spices and blending with papaya .
literature studies on aloe gel administration to human subjects recommend about 30  ml consumption per day .
since the average consumption of a beverage for an individual could be about 100  ml and also because addition of ag at higher levels was more acceptable , 30 sagpb was chosen for further storage studies .
the control spiced papaya beverage ( spb ) and 30% aloe gel - papaya spiced beverage blend ( sagpb ) were periodically analyzed for various parameters on storage and results are discussed in the following section .
the initial titratable acidity of the samples was found to be 0.27% . with an increase in storage time ,
this could be attributed to the decomposition of fermentable substrate , especially , carbohydrates in the fruits and added sugar , thereby increasing the acidity . significantly ( p < 0.05 ) lower acidity was recorded in sagpb throughout the storage period .
spb was found to exhibit a higher increase in acidity to 0.62% , compared to the acidity value of 0.54% in sagpb , after 150  d of storage .
similar increase in acidity on storage has also been reported in other beverages such as jamun   and other fruit flavored drinks .
total soluble solids on the initial day were similar in spb ( 15.6  brix ) and sagpb ( 15.7  brix ) , respectively ( table 2 ) .
similar to titratable acidity , spb recorded a higher tss throughout storage compared to sagpb .
a significantly ( p < 0.05 ) lower tss of 18.7  brix was recorded in the sagpb compared to spb ( 25.2  brix ) .
the increase in tss observed on storage could be due to the conversion of polysaccharides to sugars .
this could have also led to an increase in total and reducing sugar content on storage .
the spb beverage recorded an increase in total sugar content from 16.7% on the initial day to 29% at the end of storage period .
this increase was lesser in case of sagpb from 17% to 24.5% from 0  d to 150  d of storage .
similarly the initial reducing sugars content of the beverages was found to range from 6.7% to 6.9% which increased to 11% and 9.5% for spb and sagpb , respectively .
an increase in reducing sugars has also been reported in case of whey - based banana herbal beverage during storage .
the instrumental color of the samples was determined in terms of the l , a , and b values . in the papaya beverage ,
the predominant color is orange - red and , hence , + a value which denotes redness is the most important parameter , followed by + b which denotes yellowness . a higher a value of 2.36 was recorded in the sagpb compared to spb ( 1.63 ) on the initial day ( table 2 ) .
the sagpb samples could maintain higher a scores of 1.3 , significantly higher than spb ( 0.61 ) by the end of storage period .
a decreasing trend was also witnessed in b values from 9.23 to 7.83 in spb and from 11.9 to 9.3 sagpb , from the initial to final day of storage , respectively .
the sagpb samples successfully maintained significantly higher b value during storage , thereby resulting in a brighter and more acceptable product .
another important parameter critical during storage is nonenzymatic browning ( neb ) which has been reported to be caused due to maillard reaction and degradation of pigments .
an increase in neb on storage was seen in both the samples , though the extent of browning was significantly higher in the spb samples compared to sagpb ( table 2 ) .
the aloe gel enriched beverage ( sagpb ) recorded 35% lower neb which could be attributed to the beneficial effect of aloe gel addition .
aloe gel has been reported to have an antibrowning functionality when applied as a coating on whole   and minimally processed fruits .
the phytochemicals evaluated in the beverages on storage include vitamin c , total polyphenols , and total flavonoids .
the initial content of vitamin c recorded in the samples on the initial day was 5.22  mg/100  ml and 5.31  mg/100  ml for spb and sagpb , respectively .
a reduction in ascorbic acid on storage was observed , which has been reported to be mainly caused due to anaerobic degradation , especially in thermally preserved products . similar reduction in vitamin c content has also been reported in other fruit juices such as orange juices .
a gradual reduction on storage led to the vitamin c content becoming 74% lower after 90  d and 79% lower after 150  d of its initial value in spb samples .
however , in sagpb , the reduction was lower ( 56% lower on 90  d and 61% lower on 150  d than the initial value ) .
aloe gel is reported to have good antioxidant activity   and , hence , could have protected vitamin c from oxidation to some extent during storage .
the content of total polyphenols in the beverages was found to be 235  mg/100  ml and 240  mg/100  ml for spb and sagpb , respectively , on the initial day .
polyphenol content of both the beverages was found to initially increase on storage up to 45 days in spb and 90 days for sagpb , after which there was a decrease .
the flavonoid content showed similar trend , that is , increases up to 45 days of storage , followed by decrease . after 150 days of storage , sagpb demonstrated 15.6% and 23% higher polyphenol and flavonoid contents , respectively , significantly higher than spb .
very little information is available in literature regarding the phenolic content of papaya rts beverage on storage .
the increase in phenolic content on storage could be due to the release of the free acids from their bound forms .
similar observations have also been reported for some individual phenolic compounds on storage . in a study by klimczak et al . , an increase in the concentration of p - coumaric acid and ferulic acids was observed during 6-months storage at 18 , 28 , and 38c in orange juice .
the same study also reported an increase in concentration of sinapic acid for 4 months after which there was a decrease , a trend similar to the one observed in the present study ( i.e. initial increase followed by decrease ) .
other studies also report an increase in concentration of phenolic compounds , particularly p - coumaric acid and ferulic acids on storage [ 23 , 24 ] .
since changes in individual phenolic constituents contribute to the overall phenolic content of the beverages , the results observed in the present study could be compared to those reported in literature for individual phenolic compounds . in the present study ,
the spectrophotometric method using folin - ciocalteu reagent was employed to determine the total phenols as it is a routine analytical tool used widely for estimating differences in polyphenols among fruits , vegetables , and their products . however , this method lacks sensitivity   and , hence , could react with other reducing compounds such as carotenoids , sugars , and vitamin c   present in fruits and fruit products . in the present study
the positive health effects of polyphenols and flavonoids have been well explored in the past decade .
a higher content of these phytochemicals in the aloe gel enriched beverage indicates the beneficial role of aloe gel as a functional ingredient in fruit based beverages .
both the beverage samples were found to be free from microbial proliferation till the end of storage period in terms of standard plate count and yeast and mold count , thereby indicating its fitness for consumption even after 5 months of storage .
this could be attributed to the effective pasteurization treatment , addition of citric acid which acts as a preservative , and also due to the addition of spices which are known to possess good antimicrobial activity [ 7 , 8 ] .
the combined beneficial effect of the above mentioned factors could have led to the higher product stability observed in both the samples .
the results of the sensory acceptability of the spb and sagpb on storage have been depicted in figure 1 .
no significant differences were observed between the samples initially , except in terms of taste and flavor wherein sagpb scored higher due to its balanced taste .
results indicated maintenance of fresh sensory quality in aloe gel enriched beverage for a longer period compared to control beverage .
end of storage was marked by significant differences between the samples for all the parameters evaluated primarily the taste and flavor .
the spb beverage scored lower in taste and flavor mainly due to the sour / acidic taste which increased on storage .
this could be evidenced in the chemical analysis results which revealed spb to have higher acidity value .
on the other hand , the sagpb sample maintained the balanced taste with only slight change in the acidity thereby recording higher scores for taste and flavor .
the overall acceptability of sagpb was significantly higher ( 4 ) compared to spb ( 2.9 ) at the storage period , demonstrating the beneficial effect of aloe gel addition on maintaining the sensory quality of the developed beverage .
this present study revealed various beneficial effects of aloe gel incorporation to spiced papaya beverage .
the effects include better product quality characteristics ( physicochemical , sensory , and microbial quality ) , enhanced phytochemical profile , and improved storage stability .
aloe gel could thus be used to deliver natural bioactive phytochemicals to formulate functional fruit beverages .
aloe - fruit beverage blends could also offer an attractive means of increasing the consumption of unpalatable aloe gel / juice .
the developed aloe gel - fruit based spiced functional beverage blend could be promoted as a nutraceutical product with multiple benefits to the consumers .
 
 aloe vera gel , well known for its nutraceutical potential , is being explored as a functional ingredient in a wide array of health foods and drinks . 
 processing of exotic fruits and herbal botanicals into functional beverage is an emerging sector in food industry . 
 the present study was undertaken to develop a spiced functional rts beverage blend using aloe gel ( ag ) and papaya . 
 aloe gel ( 30% ) , papaya pulp ( 15% ) , spice extract ( 5% ) , and citric acid ( 0.1% ) were mixed in given proportion to prepare the blend with tss of 15 brix . 
 the product was bottled , pasteurized , and stored at room temperature . 
 the quality characteristics and storage stability of the spiced beverage blend ( sagpb ) were compared with spiced papaya rts beverage ( spb ) . 
 periodic analysis was carried out up to five months for various physicochemical parameters , sugar profile , bioactive compounds , microbial quality , instrumental color , and sensory acceptability . 
 the sagpb exhibited superior quality characteristics compared to spb both in fresh and in stored samples . 
 the spb was acceptable up to four months and sagpb for five months . 
 the results indicate that nutraceutical rich ag could be successfully utilized to develop functional fruit beverages with improved quality and shelf life . 
1. Introduction
2. Materials and Methods
3. Results and Discussion
4. Conclusions