富γ-氨基丁酸乳酸菌发酵功能饮料的研制

以糙米汁、黄豆芽汁和牛奶酶解液为培养基生产的富含γ-氨基丁酸乳酸菌发酵液为原料,进行功能饮料研制。优化得到的GABA功能饮料配方为:乳酸菌发酵液5%、枸杞汁40%、苹果汁40%、复合甜味剂3%、柠檬酸0.10%。经0.25%(w/v)的明胶和0.25%(w/v)的单宁澄清后,饮料于室温放置60d未出现浑浊和沉淀等现象。模糊综合评价表明,GABA功能饮料符合消费者的饮用要求。     

Effects of various clarification treatments on phenolic compounds and color of apple juice

The purpose of this study was to investigate the changes that occur during conventional clarification using gelatin, bentonite, silica sol, and water-soluble chitosan on the phenolic compounds, antioxidant activity, and color of apple juice. The apple material used in this study was of two varieties: Sampion and Idared. The changes in the polyphenols composition (procyanidins, hydroxycinnamic derivatives, and dihydrochalcones) were monitored through the clarification process. Sampion apple control juices contained more total polyphenols than do Idared apple juices. In Sampion variety apple juice, the dominant polyphenols are the flavan-3-ols (86% of total polyphenols), followed by hydroxycinnamic acids (9.7%), dihydrochalcones (3.0%), and flavonols (1.3%). In Idared apple juice the hydroxycinnamic acids (especially chlorogenic acid) are dominant (about 48% of total polyphenols), followed by flavan-3-ols (40%). However, the concentration of polymeric procyanidins in Sampion apple juices was 62.8 and 46.3% less when the Profloc (chitosan) and gelatin treatments were used, respectively. Aktivbentonit and Puranit (bentonite) supplementary added in juices clarification have some protective effect on polymeric procyanidins only with Profloc treatment. That kind of effect was not observed in Idared apple juices with almost eight times smaller polymeric procyanidins concentration than in Sampion apple juices. The antioxidant activity, measured by the DPPH (1,1-diphenyl-2-picrylhydrazyl radical) method, ranged from 0.20 mg TEAC/mL in Idared apple juice to 0.30 mg TEAC/mL in Sampion apple juice, measured by the ABTS method, from 0.17 to 0.48 mg TEAC/mL, respectively. Clarification of apple juices with chosen clarifying agents has statistically no significant (p>0.05) influence on antioxidant capacity. This study suggests that chitosan can be used as a conventional clarifying aid of apple juices and that treatment has no impact on their biochemical parameters.     

Effect of processing on post-bottling haze formation in apple juice

Post-bottling haze formation in clarified apple juice produced under a variety of processing conditions was studied. Turbidity of the juice was monitored at intervals during a 6-month storage period. Changing the pasteurization temperature of raw juice and omitting the addition of amyloglucosidase did not retard or prevent haze development. Omission of the fining procedure, however, resulted in an increase in turbidity of 1.36 NTU and visual observation of larger quantities of haze. Fining with a gelatin/bentonite ratio of 1:1 gave the least haze. Thermocoagulation treatment applied to the juice prior to ultrafiltration also did not retard or prevent haze formation. Ultrafiltration at lower processing temperatures resulted in the development of less haze. At higher temperatures an increase in turbidity of over 14 NTU was observed. The results suggest that optimization of the fining procedure and ultrafiltration could be used to retard post-bottling haze in apple juice.     

Kinetics of haze formation and factors influencing the development of haze in clarified apple juice

The rate of haze formation in commercial clarified apple juice stored at 4, 25 and 37°C was monitored over a 16 to 35-week storage period. Changes in turbidity, tannin content and browning index were evaluated. The juice appeared virtually clear and had very little colloidal particles during the initial stages of storage. After 24 weeks, an increase in turbidity of 2.32 NTU was observed for juice samples stored at 37°C. An increase of 0.58 and 0.95 NTU was observed for samples stored at 25 and 4°C, respectively. There was a general decrease in tannin content and an increase in browning index with storage; this effect was most pronounced for samples stored at 37°C. The rate of haze formation and tannin depletion in juice samples followed first-order reaction kinetics. Light and headspace did not affect haze formation. NaCl and CaCl₂ increased haze development while sucrose (up to 60%), urea (0.5 M), and EDTA (up to 0.01 M) had little effect. Addition of sodium dodecyl sulfate retarded haze formation.     

Defining the stability interfaces of apple juice: Implications on the optimisation and design of High Hydrostatic Pressure treatment

In this article an experimental approach is applied to determine the impact of High Hydrostatic Pressure (HHP) processing (350 to 550 MPa at 20 °C and for 1 to 25 min of holding time) on the survival of Issatchenkia orientalis and the spoilage of apple juice (with 300 ppm added ascorbic acid) during different storage conditions, i.e., 4 to 12 °C and 0 to 36 days of storage. Probabilistic modelling approaches based on logistic regression models were developed in order to describe quantitatively the spoilage/no spoilage and survival/death interfaces. For a microbially stable processed apple juice treated at 400 MPa, 10 °C and a holding time of 15 min the degradation kinetics of vitamin C were described quantitatively during subsequent storage at 4, 8, 12 °C. The rate of vitamin losses were highly reduced after the first 13 days of storage. The stability of the apple juice with respect to browning and cloudiness was evaluated by studying qualitatively the activity of polyphenol oxidase (PPO), and pectin methyl esterase (PME) enzymes at combined treatments of HHP and temperature (10 to 50 °C, HHP at 750 MPa and holding time from 1 to 25 min). The highest achieved reduction of PPO and PME was 51.47% and PME 81.44%, respectively.

Industrial relevance

This paper demonstrates an approach based on quantitative probabilistic and qualitative studies for defining the stability interfaces of apple juice. Its applicability contributes on the design and optimisation of High Hydrostatic Pressure treatments.     

Radio frequency electric fields processing of orange juice

The non-thermal process of radio frequency electric fields (RFEF) has been shown to inactivate bacteria in apple juice at moderately low temperatures, but has yet to be extended to inactivate bacteria in orange juice. An 80 kW RFEF pasteurizer was used to process pulp-free orange juice at flow rates of 1.0 and 1.4 l/min. Escherichia coli K12 in orange juice was exposed to electric field strengths of 15 and 20 kV/cm at frequencies of 21, 30, and 40 kHz. Ascorbic acid (Vitamin C) content and color of the juice before and after treatment were analyzed. Electrical energy costs were calculated using the measured voltage and current. An energy balance was performed using the inlet and outlet temperatures. Processing at an outlet temperature of 65 °C reduced the population of E. coli by 3.3 log relative to the control. Increasing the treatment time and temperature and decreasing the frequency enhanced the level of inactivation. Varying the electric field strength over the range of conditions used had no effect on the inactivation. No loss in ascorbic acid or enzymatic browning was observed due to RFEF processing. The electrical energy determined using the voltage and current was 180 J/ml. This was in good agreement with the energy calculated using the temperature data. The electrical cost was $0.0026/l of orange juice. The results provided the first evidence that the RFEF process inactivates bacteria in orange juice at moderately low temperatures.

Industrial relevance

The RFEF process has been shown to inactivate E. coli in apple juice at moderately low temperatures, but has yet to be extended to inactivate bacteria in orange juice. An RFEF pilot plant pasteurizer was used to process orange juice at rates of up to 1.4 l/min. RFEF processing reduced the population of E. coli by 99.3% at 60 °C and a hold time of 3 s, whereas conventional heating at the same conditions had no effect on the E. coli. This work demonstrated that the non-thermal RFEF process can be extended to inactivate bacteria in orange juice.     

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.     

Characteristics of the gelatin extracted from Channel Catfish (Ictalurus Punctatus) head bones

Three gelatins were prepared from channel catfish head bones by hot water after the head was pretreated with alkali protease, quickly desalted by 0.4 mol/L HCl and soaked in 9 g/L Ca(OH)₂. The extraction conditions of gelatins were 5 °C, pH 4.0, 4 h, 82 °C, pH 2.5, 2 h and 90 °C, pH 3.0, 3 h, respectively. The studies showed there were many differences between these gelatins. The first head bone gelatin contained high content of imino residues and more high molecular weight proportions of β and γ components. Gel strengths of the second and third gelatins were 209 ± 7 g and 117 ± 5 g, lower than that of the first head bone gelatin (282 ± 11 g). Furthermore, the first head bone gelatin achieved the highest gelling and melting points. The first head bone gelatin showed strong ability of clarification when it was used to clarify apple juice. At the same time, the nutritional components of apple juice changed a little except Vitamin C.     

Influence of technological processing on apple aroma analysed by high resolution gas chromatography–mass spectrometry and on-line gas chromatography-combustion/pyrolysis-isotope ratio mass spectrometry

Extracts obtained by simultaneous distillation extraction (SDE) from industrial raw materials, namely single strength apple juices, and concentrates and aromas made thereof (each n = 31, from one production line; origin Poland, Germany, Turkey, Romania and China), as well as commercially available juices (n = 27), were analysed by standard controlled capillary gas chromatography–mass spectrometry (HRGC–MS). During the technological processing from juice to the aroma, no qualitative changes in the apple aroma profile were observed. Major constituents of the juices and aromas under study were found to be 1-hexanol (juice, 0.06–5.9 mg/l; aroma, 47–685 mg/l), 1-butanol (juice, 0.1–4.7 mg/l; aroma, 17–370 mg/l); E-2-hexenol (juice, 0.01–3.4 mg/l; aroma, 12–300 mg/l); E-2-hexenal (juice, 0–3.0 mg/l; aroma 0–470 mg/l), and butyl acetate (juice, 0–1.7 mg/l; aroma, 0–165 mg/l). By far the major component of the apple juice concentrates under study was furfural (2.4–56 mg/kg). The observed occurrence of 3-methyl-1-butanol (juice, 0.01–2.1 mg/l; aroma, 1.5–134 mg/l) and, in part, its acetate (juice, 0–0.3 mg/l; aroma, 0–3.3 mg/l), both known not to be genuine apple constituents, was obviously caused by fermentative effects in the course of industrial juice production. In addition, on-line capillary gas chromatography–isotope ratio mass spectrometry was used in the combustion (C) and the pyrolysis (P) modes (HRGC–C/P–IRMS) for the determination of δ¹³C_V-PDB and δ²H_V-SMOW values of selected apple flavour constituents to check potential isotope discrimination during distillative aroma production. As shown by means of the representative examples of E-2-hexenal, 1-hexanol and E-2-hexenol, their δ²H_V-SMOW values were slightly depleted. However, authenticity assessment by stable IRMS will not be influenced by this effect.     

The effects of processing technology on the patulin content of juice during commercial apple juice concentrate production

 The effects of different treatments on the patulin content of apple juice during the production of industrial apple juice concentrate were investigated. Conventional clarification using a rotary vacuum precoat filter was found to be more effective than using ultrafiltration for the removal of patulin from apple juice. The average losses of patulin were 39% and 25% for conventional clarification and filtration, and ultrafiltration, respectively. Washing and handling appeared to be the most critical steps in removing patulin from apples since up to 54% could be removed using high-pressure water spraying. Received: 22 January 1998 / Revised version: 21 April 1998     

Cross-flow Microfiltration with Gas Backwash of Apple Juice

Cross-flow microfiltration (MF) was applied for clarification of commercially pressed depectinized apple juices and pectin containing artificial apple juice suspensions under continuous low pressure inlet conditions (35 kPa - 209 kPa). Periodic gas backwash (air or N₂) removed solids from exteriors of 0.2 μm cut-off hollow fiber polypropylene membranes. Flux and nephelos turbidity units (NTU) of filtrates for both commercial juices and artificial juices were evaluated. Commercial juices after vacuum filtration and MF had 100–110 L/m²/hr flux during 2 hr operation. Low pectin (1%) artificial juices had ～70 L/m²/hr flux during 1.5 hr. NTUs of filtrates from all treatments were <0.69. All filtrates were commercially sterile.     

The effects of processing technology on the patulin content of juice during commercial apple juice concentrate production

 The effects of different treatments on the patulin content of apple juice during the production of industrial apple juice concentrate were investigated. Conventional clarification using a rotary vacuum precoat filter was found to be more effective than using ultrafiltration for the removal of patulin from apple juice. The average losses of patulin were 39% and 25% for conventional clarification and filtration, and ultrafiltration, respectively. Washing and handling appeared to be the most critical steps in removing patulin from apples since up to 54% could be removed using high-pressure water spraying. Received: 22 January 1998 / Revised version: 21 April 1998     

Study on the development of pomegranate juice processing technology: clarification of pomegranate juice

The effects of clarification agents and methods on pomegranate juice quality were studied. Fruits were pressed as whole, and extracted juice was clarified with gelatin, polyvinylypolypyrrolidone (PVPP) and natural sedimentation. In order to determine the effects of these clarifying techniques on product quality, pH, total phenolic substances (TPS), anthocyanin, turbidity, and total colour density tests were applied to each sample. In clarification, the main purpose was to reduce the amount of phenolic substances. Phenolic substances were controlled in each clarification method. The most effective method was the application of 1 g/L gelatine for clarification. Sensory evaluation also applied for clarified juices and gelatin application was selected by panelists to be superior.     

雪莲果汁澄清剂比较研究

为得到澄清的雪莲果汁,对5种澄清剂在雪莲果汁中的澄清效果进行了比较研究,通过比较果汁透光率、吸光度的变化,确定雪莲果汁适宜的澄清剂。试验结果表明：壳聚糖、明胶、果胶酶、单宁、硅藻土对雪莲果汁均有一定的澄清效果。其中,壳聚糖的澄清作用时间最短,澄清效果明显优于其它几种澄清剂,且对果汁品质无明显影响,其最适添加量为0.72g/L;明胶的适宜用量为1.44g/L,果胶酶为0.20g/L,单宁为0.96g/L,硅藻土为0.24g/L,这4种澄清剂的澄清效果差异并不显著。壳聚糖为雪莲果汁适宜的澄清剂。     

Effect of single and combined UV-C and ultra-high pressure homogenisation treatments on inactivation of Alicyclobacillus acidoterrestris spores in apple juice

Alicyclobacillus acidoterrestris is a spore-forming bacterium that can survive thermal pasteurization and acidic conditions. It produces changes in the odour and flavour of fruit juices leading to economical loses. A. acidoterrestris CECT 7094 spores were inoculated in clarified and cloudy apple juices (Golden delicious var.) in the range of 5–6 log₁₀ spores/mL and submitted to different short-wave ultraviolet light (UV-C) doses (7.2–28.7 J/mL) and ultra-high pressure homogenisation (UHPH) treatments (100–300 MPa), including their combination. A. acidoterrestris could be inactivated in clarified apple juice at a level of 4.8 log₁₀ CFU/mL by a 300 MPa-UHPH treatment when the inlet temperature was 80 °C. UV-C treatments showed to be more efficient achieving a lethality of 5.5 log₁₀ CFU/mL with a dose of 21.5 J/mL at 20 °C. In cloudy apple juice (2357 NTU) UV-C treatments were less efficient with a maximum lethality of 4.07 CFU/mL after a dose of 28.7 J/mL. A previous application of UHPH contributed with UV-C to obtain higher reductions of A. acidoterrestris spores at the doses of 14.3 and 21.5 J/mL compared with UV-C single treatments. On the other hand, this previous treatment also changed the properties of particles in the matrix which apparently reduced the effectiveness of UV-C at 28.7 J/mL.     

澄清方法对山萸肉澄清汁品质的影响

五种澄清方法对山萸澄清汁品质的影响表明：除酶法澄清外,自然澄清、明胶澄清、冷冻澄清均使山萸澄清汁的品质发生了劣变。     

Inactivation kinetics of apple polyphenol oxidase in different pressure–temperature domains

The impact of high hydrostatic pressure and temperature on the stability of polyphenol oxidase (PPO) was studied in cloudy apple juice. Application of 200–500 MPa near room temperature or heat treatment at 45–55 °C at ambient pressure caused an increase of PPO activity of up to 65% in freshly squeezed apple juice. Combined pressure–temperature inactivation experiments with fully activated PPO (5 min treatment at 400 MPa and 20 °C) were carried out in the range of 0.1–700 MPa and 20–80 °C. Enzyme inactivation kinetics followed a 2.2 order reaction scheme at all pressure–temperature conditions tested. A polynomial model was successfully applied to describe the rate of PPO inactivation as a function of pressure and temperature and was used to construct a pressure–temperature isokinetic diagram. This diagram clearly showed synergistic effects of pressure and temperature on the inactivation of apple PPO at pressures above 300 MPa and antagonistic effects at lower pressures. Compared to ambient pressure conditions, temperatures required to inactivate PPO in apple juice were increased 10–15 °C at 100–300 MPa.

Industrial relevance

High pressure processing of fresh fruits is gaining popularity in the food industry because of its ability to inactivate microorganisms and some enzymes near room temperature with little impact on flavour or nutritional attributes of the food. However, quantitative data regarding the impact of process parameters on the target reaction are required to economically utilise this technology. This paper provides a mathematical model describing the combined effect of pressure, temperature and treatment time on the inactivation of PPO in cloudy apple juice.     

Effects of pretreatment and various operating parameters on permeate flux and quality during ultrafiltration of apple juice

The central composite design with a quadratic model was used to investigate the effect of temperature (20–40 °C) and transmembrane pressure (TMP) (100–300 kPa) as well as pretreatment with gelatin and bentonite (0:0–300:1500 mg L^?1) on permeate flux and fouling resistance during ultrafiltration of apple juice. The changes in some physicochemical properties were also investigated. Pretreatment of apple juice with gelatin and bentonite and an increase in the temperature and TMP significantly improved the permeate flux. In general, physicochemical properties of apple juice other than polyphenolics were not affected by the applied parameters. Using 150 mg L^?1 of gelatin and 750 mg L^?1 of bentonite for fining significantly reduced the total phenolic content and so did the fouling resistance. Fouling resistance also decreased with increasing temperature, and increasing pressure increased the fouling resistance.     

苹果汁复合澄清法和壳聚糖澄清法的优化研究

研究了果胶酶复合澄清法和壳聚糖澄清法对苹果汁的澄清效果,确定了最佳工艺条件,采用优化的澄清方法,苹果汁的透光率可达98％以上。论文对不同成熟期的苹果制汁的澄清工艺进行了调整,还探讨了澄清工艺对苹果汁主要成分的影响。     

壳聚糖与黄原胶对菠萝汁澄清效果的研究

以浊度、色差和透光率为指标,壳聚糖和黄原胶为澄清剂,研究了壳聚糖/黄原胶对菠萝汁的澄清效果,确定了最佳的工艺参数,并在单因素实验的基础上,通过正交实验,得出澄清菠萝汁的最适工艺为:温度35℃,时间70min,壳聚糖(10g/L)与黄原胶(10g/L)的比例1∶1,果汁pH3.4,验证实验结果表明,此时浊度为0.93NTU,透光率高达98.5%,菠萝汁的色差b*=14.47,在此工艺条件不但能得到满意的澄清效果,还能呈现菠萝原汁的亮黄色。