Investigating the control of Listeria monocytogenes on alternatively-cured frankfurters using natural antimicrobial ingredients or post-lethality interventions

The objective of this study was to investigate natural antimicrobials including cranberry powder, dried vinegar and lemon juice/vinegar concentrate, and post-lethality interventions (lauric arginate, octanoic acid, thermal treatment and high hydrostatic pressure) for the control of Listeria monocytogenes on alternatively-cured frankfurters. Lauric arginate, octanoic acid, and high hydrostatic pressure (400 MPa) reduced L. monocytogenes populations by 2.28, 2.03, and 1.88 log10 CFU per g compared to the control. L. monocytogenes grew in all post-lethality intervention treatments, except after a 600 MPa high hydrostatic pressure treatment for 4 min. Cranberry powder did not inhibit the growth of L. monocytogenes, while a dried vinegar and a vinegar/lemon juice concentrate did. This study demonstrated the bactericidal properties of high hydrostatic pressure, octanoic acid and lauric arginate, and the bacteriostatic potential of natural antimicrobial ingredients such as dried vinegar and vinegar/lemon juice concentrate against L. monocytogenes.     

Antioxidant activity and characterization of constituents in copao fruits (Eulychnia acida Phil., Cactaceae) by HPLC–DAD–MS/MSn

Copao (Eulychnia acida Phil., Cactaceae) is an endemic species occurring in arid areas of northern Chile. The fruits are commercialized by peasants within the Elqui and Limari valleys and are appreciated for its acidic and refreshing taste. We now report the total phenolic (TP) and total flavonoid (TF) content, antioxidant activity, phenolic composition and main phenolic distribution in pulp and epicarp of copao fruits from different harvesting places from both valleys. The ascorbic acid content was determined in fresh fruit pulp, epicarp and juice. The phenolic-enriched extract was analyzed for antioxidant effect and composition. Ferulic acid, 9,10-dihydroxy-4,7-megastigmadien-3-one hexoside, isorhamnetin and quercetin glycosides were identified by HPLC–DAD–MS/MS analysis. The main compounds were isolated and fully characterized by NMR techniques. The main phenolic in the samples was isorhamnetin-3-O-[α-rhamnopyranosyl-(1 → 6)-β-glucopyranoside]. The HPLC pattern of the phenolic-enriched extracts of the fruits allows a differentiation of samples from the Elqui and Limari valleys. All fruit extracts and Amberlite-retained fraction from the methanolic extract were devoid of toxicity against human gastric AGS cells and human lung fibroblasts, with IC₅₀ values > 400 μg/mL for AGS and 344 to > 400 μg/mL for fibroblasts, respectively. The compound identification, associated with the antioxidant activity and insignificant cell toxicity, adds relevant information for the possible development of this native fruit into a new crop.     

Colour and texture of apples high pressure processed in pineapple juice

Cubes of Granny Smith and Pink Lady apples were vacuum packed in barrier bags with 0% to 50% (v/v) pineapple juice (PJ) at 20°Bx and subjected to high pressure processing (HPP) at 600 MPa for 1–5 min (22 °C). The in-pack total colour change (ΔE) was observed over 4 weeks at 4 °C. Within <1 week of storage at 4 °C, texture, polyphenoloxidase, pectinmethylesterase activities, changes in ΔE and visual browning after opening the bags during air exposure (22 °C; 21% O2 ) for 5 h were also monitored. During the 4 weeks storage in bag visible colour changes were not observed. Texture and ΔE after 5 h air exposure were significantly affected by the apple variety, HPP time and % PJ used. The combined treatment significantly reduced residual PPO activity while PME activity was not affected in both varieties. Pineapple juice in combination with HPP could be used as a natural preservation system for minimally processed apples.Industrial relevanceBrowning upon opening the packs and during air exposure can adversely affect the quality of fresh-cut fruits. Combined treatment of high pressure processing (HPP) and use of pineapple juice has the potential to prevent browning for several hours giving sufficient time for presentation and use in domestic and foodservice environment where high quality fresh-like fruit is required.     

Diversity and probiotic potentials of lactic acid bacteria isolated from gilaburu,a traditional Turkish fermented European cranberrybush (Viburnum opulus L.) fruit drink

The aim of the present study was to characterize lactic acid bacteria (LAB) strains isolated from traditional fermented gilaburu fruit juice and their probiotic potential. The LAB counts of the fermented gilaburu fruit juice were in the range of 3.92–8.30 log cfu/g. Total of 332 isolates belonging to Lactobacillus and Leuconostoc species were characterized from traditional fermented gilaburu juice by genotypic methods. It was also determined that the major LAB strains belong to Lactobacillus plantarum (173 isolates), Lactobacillus casei (52 isolates) and Lactobacillus brevis (24 isolates), while Lactobacillus buchneri, Lactobacillus parabuchneri, Lactobacillus pantheris, Leuconostoc pseudomesenteroides and Lactobacillus harbinensis were the least in isolated LAB strains. In terms of the probiotic potentials, Lb. plantarum strains were able to grow at pH 2.5, but 3 of Lb. casei strains, one of each Lb. brevis and Lb. buchneri strains could not grow at the same pH. All selected LAB stains were resistant to bile salt at ≤ 0.3% concentration. While all the LAB species grew at 15 °C, two Lactobacillus hordei strains could also grow at 45 °C. The highest cell hydrophobicity degrees were for Lb. casei (G20a) and Lb. plantarum (G19e) as 87.5 and 86.0%, respectively. Listeria monocytogenes and Bacillus cereus were the most sensitive bacteria against the selected LAB strains, while Escherichia coli and Staphylococcus aureus were the most resistant. Again all the isolated LAB species were resistant to three antibiotics; kanamycin, streptomycin and vancomycin. Characterization and probiotic potentials of the LAB isolated from fermented gilaburu (Viburnum opulus) juice were studied first time, and further research needs to be done on their behaviors in similar food formulations as a probiotic.     

Processing of clear and turbid grape juice by a continuous flow UV system

The inactivation of inoculated (S. cerevisiae) and spoilage microorganisms, i.e. yeasts and lactic acid bacteria (LAB), in clear and turbid grape juice was investigated using a pilot scale UV system. The biodosimetry method was used for UV dose prediction in a continuous flow UV reactor. Weibull model was applied for fitting the inactivation data. The flow rates (774, 820 ml/min) in this system were very close to the ones used in fruit juice processing. S. cerevisiae in clear juice was reduced by 3.39 ± 0.04 at 65.50 mJ/cm² of UV dose. 1.54 ± 0.04 and 1.64 ± 0.03 log CFU/ml reductions were obtained for spoilage yeasts and LAB in turbid juice at UV dose of 78.56 and 67.97 mJ/cm², respectively. The soluble solids (°Brix) and pH of grape juice samples were not affected by UV-C treatment (p > 0.05). Although the color parameters slightly were changed after irradiation, the color of PCGJ and FSTGJ did not show visual difference compared to the untreated samples.Industrial relevanceUV light has a potential to reduce the levels of microbial contamination in liquid foods. Although grape juice has many beneficial health effects, it has a fairly short shelf life. Therefore, pasteurization is required. But the thermal pasteurization has some undesired effects on the juice quality. Consumer demands for high quality fruit juice with fresh-like characteristics have markedly expanded in recent years. In the current study, the microbial inactivation efficiency of a pilot scale UV system for non-thermal treatment of clear and turbid grape juice was evaluated under conservative conditions. Most of the physicochemical properties of grape juice samples were not significantly affected from UV-C treatment (p > 0.05). This would be a major advantage in the processing of nutritious juice products.     

“Ice” juice from apples obtained by pressing at subzero temperatures of apples pretreated by pulsed electric fields

The impact of apple pretreatment by pulsed electric field (PEF) on juice extraction using the freezing-assisted pressing was studied. Apple discs were PEF pretreated at electric field strength of E = 800 V/cm and then air blast frozen inside the freezer (− 40 °C). Then, pressing experiments in a laboratory-pressing chamber (2–5 bars) were started at sub-zero temperature (− 5 °C). Time evolution of juice yield and its nutritional qualities were compared for PEF and untreated apple samples. High improvements of juice yield were obtained for freeze-thawed (FT) and PEF + FT samples. The combination of PEF + pressing (5 bar) at sub-zero temperature gave optimum results for juice extraction with high levels of carbohydrates, and antioxidant bioactive compounds. At fixed value of extraction yield, Y, PEF pretreatment improved nutritional parameters. E.g., at Y = 0.6, an increase in °Brix (by ≈ 1.27), carbohydrates (by ≈ 1.42), total phenolic compounds (by ≈ 1.16), flavonoids (by ≈ 1.09) and antioxidant capacity (by ≈ 1.29) was observed after PEF pretreatment.Industrial relevancePressing constitutes one of the most commonly used technologies at industrial scale to obtain fruit juices. However, during the pressing some undesirable chemical, physical and biological changes may occur in juices, thus reducing their nutritional and sensorial properties. For instance, the use of freezing-assisted pressing is a promising technique for the production of juice concentrates rich in sugars and other solids as the low temperature operation prevents undesirable modifications. But this method is rather expensive and requires strong control of the quality of “ice” juices, their sensory and compositional profiles. Thus, there is an increased search for obtaining new efficient methodologies for producing high quality juices. In this line, PEF-assisted pressing has been shown as a useful technology to increase juice yield. Therefore, the combination of PEF-assisted “ice” juice extraction by pressing of fruits at subzero temperatures may be a useful tool to improve the extraction yield of juices, thus improving their nutritional, physicochemical and sensorial properties.Keywords: “Ice” juice, Apple, Pulsed electric fields, Freezing-assisted pressing     

Polyphenols,carotenoids, and ascorbic acid in underutilized medicinal vegetables

The polyphenols, carotenoids, ascorbic acid, and protein were determined in 24 underutilized medicinal vegetables from Indonesia. Anacardium occidentale, Sauropus androgynus (L.) Merr., and Moringa pterygosperma Gaertn. leaves were rich sources of flavonoids, with 118–144 mg/100 g fresh weight. Quercetin, kaempferol, and chlorogenic acid were the predominant polyphenols among those measured in vegetables. Polyscias pinnata leaves and Solanum torvum Swartz fruits had the most phenolic acids, with 53 and 36 mg/100 g, respectively. Moringa pterygosperma had the most carotenoids among vegetables, with 14 mg β-carotene equivalents (βCE)/100 g. Ascorbic acid content of fresh vegetables was 12.03–494.43 mg/100 g. A. occidentale, S. androgynus, Ocimum americanum L., Cosmos caudatus H.B.K., and Carica papaya L. (papaya) leaves had more than 100 mg ascorbic acid/100 g. Thus, a number of underutilized vegetables from Indonesia may be rich sources of functional components including polyphenols and ascorbic acid.     

Change regime of aroma active compounds in response to pulsed electric field treatment time,sour cherry juice apricot and peach nectars,and physical and sensory properties

Regime (direction, amount, rate, and pattern) of change in aroma active compounds was quantified as a function of four pulsed electric field (PEF) treatment times, three fruits, and 10 physical and eight sensory properties using the best-fit multiple linear regression (MLR) models. The PEF treatment times did not deteriorate 94% of the sensory properties and 70% of the physical properties and significantly change 57% of a total of 73 aroma active compounds detected for sour cherry juice, and apricot and peach nectars. The best performing MLR models belonged to 1-methyl-4-prop-1-en-2-ylcyclohexene as a function of fruit type, treatment time, and titratable acidity (= 49 mg/L; R_adj² = 95.7%; R_cv² = 94.9%) and to 2-[(2S,5S)-5-ethenyl-5-methyloxolan-2-yl]propan-2-ol as a function of fruit type, and treatment time (SE = 157 mg/L; R_adj² = 98.2%; R_cv² = 98.0%), respectively (n = 48; p < 0.001).Industrial relevancePulsed electric field (PEF) is one of the leading nonthermal food technologies especiallyfor processing of high acid low viscosity foods with satisfactory quality and microbial inactivation. It was shown in this study that PEF with different treatment times can successfully be applied in the pasteurization of sour cherry juice, and apricot and peach nectars with minimum loss of aroma active compounds and sensory and physical properties. Both PEF processing conditions and results can be used as a guide to determine PEF processing parameters for industrial scale processing of juices/nectars.     

Phytonutrient,Antioxidant and Mineral Composition of Some Wild Fruits in South West Nigeria

This study was carried out to determine the chemical composition, antinutrient and phytonutrient contents of some wild fruits, namely African star apple (Chrysophyllum albidum G. Don.), hog plum (Spondias mombin Linn.), bush mango (Irvingiagabonensis Baill) and monkey cola (Colamillenii K. Schum). Samples of the wild fruit commonly consumed were collected from some villages in Ido Local Government Area, Oyo State Nigeria. The wild fruits were analysed for phytonutrients, antioxidants and mineral composition. Ranges of total phenolics and total anthocyanin content of these wild fruits were 27.78 ± 6.01 in I. gabonensis, 57.42 ± 4.47 in S. mombin, 121.29 ± 4.97 in C. millenii and 398.23 ± 0.00 in C. albidum respectively. Significant differences (p < 0.05) were found in antinutrient, phytonutrient and mineral composition of C. albidum, I. gabonensis and C. millenii. The analysis of variance revealed that calcium and manganese contents of I. gabonensis were significantly (p < 0.05) higher than those of C. albidum and C. millenii. The antioxidants especially vitamin C content ranged from as low as 15.87 mg/100 g in C. albidum to as high as 204.86 mg/100 g in S. mombin. The values for total carotenoid ranged from 172.77 μg/100 g (in C. millenii) to 1380.17 μg/100 g (in C. albidum). The wild fruits are sources of phytonutrients, antioxidants such as vitamin C, total carotenoids and some minerals. Planting of the wild fruit trees or the incorporation in farming systems should thus be encouraged to increase production and availability to consumers and as industrial raw materials.     

Inactivation of food spoilage bacteria and Escherichia coli O157:H7 in phosphate buffer and orange juice using dynamic high pressure

This study aimed to evaluate the potential of dynamic high pressure (DHP) technology to inactivate pathogenic and spoilage microflora in orange juice. Escherichia coli O157:H7 ATCC 35150, Lactobacillus plantarum ATCC 14917, Leuconostoc mesenteroides ATCC 23386 and two orange juice isolates: Saccharomyces cerevisiae and Penicillium ssp. were subjected individually to different DHP treatments. The effectiveness of DHP treatment was first evaluated in phosphate buffered saline (PBS) before application in orange juice samples. The inactivation efficacy of DHP depended on the pressure applied and the number of passes. It was more efficient against Gram-negative strains than Gram-positives. Complete inactivation and 5 log reduction of E. coli O157:H7 were achieved in orange juice at 200 MPa after 5 and 3 passes at 25 °C, respectively. Lower inactivation was obtained with Penicillium ssp. (4 log), S. cerevisiae (2.5 log), L. plantarum (2.3 log) and L. mesenteroides (1.6 log). The gathered results revealed the potential of DHP to inactivate all the tested microorganisms and then, it could constitute a promising alternative technology for cold pasteurization of fruit juices.     

Important flavonoids and limonin in selected Thai citrus residues

The distributions of important flavonoids and limonin in selected Thai citrus residues were investigated in this study. The residues of interest were peels of pomelo (Citrus grandis (L.) Osbeck cv. Kao Yai and cv. Kao Nampheung), residues after juice extraction of tangerine (Citrus reticulata Blanco cv. Sainamphueng and cv. Bangmod) and peels and residues after juice extraction of kaffir lime (Citrus hystrix DC). Flavonoids were characterized and quantified in terms of flavanones, i.e., naringin and hesperidin, and polymethoxyflavones (PMFs), i.e., nobiletin, sinensetin and tangeretin. Naringin was a dominant flavanone in polmelo peels. Three PMFs were found in all samples with varying contents. Comparing the samples, residues from tangerine cv. Bangmod exhibited the highest value of each PMFs. Limonin was present in small amounts in pomelo peels and residues after juice extraction of tangerine and kaffir lime. All samples were good sources of dietary fibre, with a total dietary fibre content of more than 60 g/100 g on a dry weight basis with high proportion of soluble dietary fibre.     

The properties and stability of anthocyanins in mulberry fruits

Mulberry fruit is well known as a good source of anthocyanins with many biological activities. However, there are several colors of mulberry fruits, even from the same species, which may generate different amounts of anthocyanins. This study investigates anthocyanin content and antioxidant levels as well as tyrosinase inhibition activity in the extract from various colors of mulberry fruit, Morus alba. The effects of heat and light, which the extract may be exposed to during food processing, on anthocyanin and antioxidant activities are also evaluated. Our results show that purple-colored mulberry fruit extract contains the highest levels of anthocyanin and strongest antioxidant as well as anti-tyrosinase properties compared with other colors mulberry fruit extracts. Light or heat exposure by incubation of the mulberry fruit extract at 70 °C for 10 h significantly deteriorated total anthocyanin and ascorbic acid content and led to a corresponding increase of the IC₅₀ values.     

Colour studies on fruit juice blends from Opuntia and Hylocereus cacti and betalain-containing model solutions derived therefrom

The visual appearance and pigment stability of fruit juice blends from Opuntia and Hylocereus cacti and of betalain-containing model solutions derived therefrom were investigated at pH values ranging from 3 to 7. All samples were found to be stable as indicated by betalain contents as well as hue and chroma values over the complete pH range monitored. Both the juice and the purified betaxanthin solution from Opuntia ficus-indica cv. ‘Gialla’ were characterised by yellowish hues, while the juice and the purified betacyanin solution from Hylocereus polyrhizus displayed purplish tonalities. By blending the betaxanthin and betacyanin stock solutions, tailor-made hues covering the entire spectrum from bright yellow (h° = 84) to purplish-blue (h° = 333) were successfully produced. Since mixtures from purified betalains did not provide colour shades different from those obtained with raw cactus fruit juices, the use of the latter should be preferred both because of consumer-friendly labelling and improved pigment stability.     

Silicon Rich Rice Hull Amended Soil Enhances Anthracnose Resistance in Tomato

Silicon (Si) has proven to be effective in controlling diseases in many crops and can be used as a substitute of fungicides. It has been shown that rice hull could be applied to the soil as a non-hazardous silicon rich source in crop production. This study was conducted to investigate the effect of half burnt rice hull (HBRH) as a silicon source in suppression of anthracnose in tomato and understanding underlying mechanisms of disease resistance. HBRH was made by burning raw rice hull at 250 ^°C for 15 minutes. Six different levels of HBRH: 0, 5, 10, 15, 20 and 25 g per 1 kg of soil were incorporated into soil along with Department of Agriculture (DOA) recommended levels of NPK fertilizers. The resistance against anthracnose disease was evaluated by measuring the lesion area of tomato fruits followed by the challenged inoculation with Colletotrichum dematium for 10 days after inoculation. The mechanism behind Si induced resistance was studied by measuring the fruit firmness and cuticle thickness (CT). A significant reduction (at P ≤ 0.05) of anthracnose disease (87 and 77%) was observed in inoculated fruits of 25 and 20 g HBRH per 1 kg of soil treatments. Onset of the disease was delayed by 4 and 3 days after inoculation in fruits obtained from 25 and 20 g HBRH treated plants compared to the control. The increase of fruit firmness and CT were significant in 25 and 20 g HBRH per 1 kg of soil provided fruits. Consequently, these results suggest that HBRH is a Si rich source and 20 g HBRH per 1 kg soil would be sufficient in suppressing tomato anthracnose caused by C. dematium and the resistance might have triggered with silicon induced thicken cuticle and increased fruit firmness.     

Citharexylum solanaceum fruit extracts: Profiles of phenolic compounds and carotenoids and their relation with ROS and RNS scavenging capacities

Citharexylum solanaceum is a native fruit from Brazil, which both bioactive compounds and antioxidant potential were not yet investigated. Thus, the freeze-dried extracts of seed and pulp + skin of C. solanaceum fruits were obtained after solid-liquid extraction with ethanol and their bioactive compounds composition, namely phenolic compounds and carotenoids, were determined. The antioxidant capacity of both extracts against physiologically relevant reactive oxygen species (ROS) and reactive nitrogen species (RNS) was further investigated. Both C. solanaceum extracts showed high contents of phenolic compounds; however, pulp + skin extract presented 2.4-times more phenolic compounds (33.54 mg/g) than the seed extract (14.09 mg/g). Verbascoside (phenylpropanoid) was the major compound identified in both extracts (11–25 mg/g). Regarding the carotenoid composition, all-trans-lutein (14–42 μg/g) and all-trans-β-carotene (13–44 μg/g) were the major compounds in both extracts. The high content of phenolic compounds and carotenoids in pulp + skin extract might explain its higher scavenging capacity against all the ROS/RNS as compared to seed extract. In general, both extracts showed better scavenging capacity for the RNS than for the ROS. Our results indicate that C. solanaceum fruits can be explored as an important natural source of antioxidant compounds.     

Flavanone glycosides in Brazilian orange juice

Authentic samples of oranges, frozen concentrated orange juice and pulp-wash, and retail samples of freshly squeezed orange juice and frozen concentrated orange juice have been collected in Brazil and analysed for the flavanone glycosides (FG) narirutin and hesperidin by reversed phase HPLC with UV detection at 280 nm. The juice from hand-squeezed fruit gave narirutin and hesperidin concentrations of 16–142 mg l⁻¹ and 104–537 mg l⁻¹, respectively. The ratio of hesperidin to narirutin showed varietal difference with Pera having the highest ratio (mean 8.4) and Baı́a the lowest (3.6). Frozen concentrated orange juice contained higher quantities of FG with narirutin ranging from 62 to 84 mg l⁻¹ and hesperidin from 531 to 690 mg l⁻¹ (after dilution to 12 °Brix). In frozen concentrated orange juice pulp-wash, the narirutin level ranged from 155 to 239 mg l⁻¹ and hesperidin from 1089 to 1200 mg l⁻¹. The analysis of 23 samples of freshly squeezed juice from the Brazilian market place showed that the FG content of most samples (9.1 to 94.8 and 105.8 to 586.6 mg l⁻¹, respectively, for narirutin and hesperidin) was similar to those found for authentic ones, indicating that these orange juices were not adulterated.     

Pasteurization of citrus juices with ohmic heating to preserve the carotenoid profile

This study was carried out to assess, for the first time, the effect of ohmic heating on the carotenoid profile of two citrus fruit juices: grapefruit and blood orange. Two heat treatments were designed to obtain pasteurization values of 50 and 150 min (Tref = 70 °C and z-value = 10 °C) with ohmic heating as compared to conventional heating. The results showed that xanthophyll losses could reach 70% for epoxyxanthophylls (cis-violaxanthin and cis-antheraxanthin) and 40% for hydroxyxanthophylls (β-cryptoxanthin, lutein, and zeaxanthin) with conventional heating, but losses were under 30% and 20%, respectively, with ohmic heating. Carotene species (lycopene and β-carotene) were stable regardless of the treatment. No negative non-thermal effects of ohmic heating were shown on carotenoids. Loss simulations of the studied carotenoids showed that the high temperatures reached with ohmic heating during pasteurization could substantially increase the organoleptic and nutritional quality of acid carotenoid-rich juices.Industrial relevanceCitrus are the top fruit crops in terms of world trade. This craze for them -particularly orange and grapefruit- is notably due to their high content in organoleptic and nutritional compounds of interest and among them carotenoids. About 50% of the Citrus production is processed in juice. From the growing variety of products, minimal processed juices now have a significant market share. This work assessed for the first time the effect of ohmic heating, a thermal method for stabilizing juices while minimizing the impact on the juice quality, on the carotenoid profiles of blood orange and grapefruit juice. Pasteurization with ohmic heating was proven to be a very good alternative for protecting carotenoids and especially xanthophylls compared to conventional heating. These results will help in designing ohmic heating process parameters for optimizing the overall quality of carotenoid-rich fruit juices.     

Comparative study on cloudy apple juice qualities from apple slices treated by high pressure carbon dioxide and mild heat

Qualities of cloudy apple juices from apple slices treated by high pressure carbon dioxide (HPCD) and mild heat (MH) were evaluated. Temperatures were from 25 to 65 °C, time 20 min, and pressure 20 MPa. Polyphenol oxidase (PPO) was completely inactivated by HPCD and its minimal residual activity (RA) by MH at 65 °C was 38.6%. RA of pectin methylesterase (PME) with HPCD was significantly lower than MH and its minimum was 18%. L value of cloudy apple juice from HPCD-treated apple slices was significantly greater than that from MH-treated apple slices, however, b value, browning degree (BD) and turbidity were lower. And no differences in a value, total soluble solids, pH and conductivity were observed. After 7-day storage at 4 °C, HPCD caused no BD alteration but a significant turbidity loss. MH increased BD at 55 and 65 °C, and led to turbidity loss from 35 to 65 °C. The turbidity was not well related to RA of PME.Industrial relevanceCloudy apple juice is one of the popular fruit juices, and it requires strict processing treatment conditions to protect its quality, especially to prevent enzymatic browning and cloud loss. HPCD is one promising novel non-thermal technique and is likely to replace or partially substitute thermal processes. This study analyzed the effect of HPCD as a pretreatment means on qualities of cloudy apple juice, including inactivating enzymes which are crucial to quality control. Available data provided in this study will benefit the fruit juice industry.     

Polysaccharide-based multilayered antimicrobial edible coating enhances quality of fresh-cut papaya

A microencapsulated beta-cyclodextrin and trans-cinnamaldehyde complex (2 g/100 g) was incorporated into a multilayered edible coating made of chitosan and pectin. Fruits were washed, peeled and cut, coated, and stored at 4 °C in Ziploc^® trays with Ziploc^® lids for 15 days. Uncoated fruits served as controls. Coated fruits were firmer, maintained color, β-carotene content, and showed lower juice leakage (P < 0.05). Coated samples were more accepted (P < 0.05) by the panelists than the controls. Encapsulation of trans-cinnamaldehyde was successful since it had no negative impact on the fruit's flavor. A parallel study evaluated the effect of packaging on the efficacy of the multilayered coating. Coated and uncoated fruits in trays were also covered with Saran^® wrap and plain cheese cloth (ambient conditions). The Ziploc^® trays with Ziploc^® lids were the best packaging method. The Layer-by-layer assembly with incorporation of microencapsulated antimicrobial was effective in extending shelf life and quality of fresh-cut papaya.     

Vanillin inhibits pathogenic and spoilage microorganisms in vitro and aerobic microbial growth in fresh-cut apples

The antimicrobial effect of vanillin against four pathogenic or indicator organisms; Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, and Salmonella enterica subsp. enterica serovar Newport and four spoilage organisms; Candida albicans, Lactobacillus casei, Penicillum expansum, and Saccharomyces cerevisiae that could be associated with contaminated fresh-cut produce, was examined. The minimal inhibitory concentration (MIC) of vanillin was dependent upon the microorganism and this ranged between 6 and 18 mM. When incorporated with a commercial anti-browning dipping solution (calcium ascorbate, NatureSeal™), 12 mM vanillin inhibited the total aerobic microbial growth by 37% and 66% in fresh-cut ‘Empire’ and ‘Crispin’ apples, respectively, during storage at 4 °C for 19 days. Vanillin (12 mM) did not influence the control of enzymatic browning and softening by NatureSeal. These results provide a new insight for vanillin as a potential antimicrobial agent for refrigerated fresh-cut fruits and vegetables.