Effect of processing and storage time on the vitamin C and lycopene contents of nectar of pink guava (Psidium guajava L.)

In this study, the effect of processing and storage time on the vitamin C and lycopene contents was evaluated. Guavas were washed, cut in quarters, blanched, pulped and the pulp pasteurized. The pulp was used for the production of nectar: guava pulp, sugar and water were mixed in 5:3:12 proportions, and the mixture was pasteurized, poured while hot into 125 mL glass jars, and cooled rapidly to 25 degrees C. The production of nectar from fresh guava reduced vitamin C, lycopene and titratable acidity, by contrast soluble solid and pH increased significant. Vitamin C content from 168.9 to 62.3 mg/(100 g fresh weight), and lycopene content from 3.55 to 1.35 mg/(100 g fresh weight) (p < 0.001 in both cases. After 240 days at 10.0 +/- 2 degrees C, no further statistically significant change in lycopene and soluble solid content was observed (p > 0.05). Storage time did affect vitamin C, pH, and titratable acidity content, vitamin C content fell by 89.3% to 6.67 mg/(100 g fresh weight) (p < 0.001). Based on this study, guava nectar storage at 10 degrees C retained 46% of the content of vitamin C for 120 days.     

Effect of fruit storage conditions on olive oil quality

"Koroneiki" olive fruit from trees grown in Crete were stored under five different conditions (0°C, air; 5°C, air; 5°C, 2% O₂+5% CO₂; 7.5°C, air; 7.5°C, 2% O₂+5% CO₂). Oil was obtained from fruit immediately after harvest and after fruit storage for 30 and 60 d. Olive oil quality was evaluated by determining acidity, peroxide value, absorption coefficients (K₂₃₂, K₂₇₀), phenol and chlorophyll content, fatty acid composition, and the resistance to oxidation by oven test. Olives stored at 7.5°C, even for 30 d, deteriorated from fungus development, and the obtained oil was of inferior quality with high acidity, peroxide value, and absorption coefficients. The same oil had high chlorophyll and phenol content, resulting in good oil resistance to oxidation. Olive oil from fruit stored at 0 or 5°C for 30 d had acceptable acidity, peroxide value, and absorption coefficients, but showed low resistance to oxidation, which was attributed to low chlorophyll and phenol content. This condition is further attributed to chilling injury caused by low storage temperatures. During storage, all treatments resulted in an increase of oleic acid, partly as a result of linoleic acid oxidation.     

Microbiological and physicochemical evaluation of pasteurized nectar elaborated with tree tomato (Cyphomandra betaceae Sendth)pulp

Tree tomato (Cyphomandra betaceae Sendth) is a species from high tropical regions. In Venezuela, it is cultivate at the Andean and Aragua state but its consumption is restricted as fruit-fresh, though it a nutritious and industrial potential due its provitamin A content. In this research four nectars were elaborated in proportion I L pulp/4 L of water (1:4) and addition of ascorbic acid (I: 0%; II: 0.5%; III: 1.0 y IV: 1.5%). The nectars were pasteurized (60 degrees C for 30 min), tuned into amber bottle, and stored under refrigeration conditions (7.0 +/- 1.0 degrees C). Weekly during 21 days the mesophilic bacteria, molds, yeasts, total coliforms (MPN/mL), pH, degree Brix, acidity, total carotenoids, vitamin C and total sugars were evaluated. The mesophilic bacteria content was < 200 UFC/mL for every formulation on the first day the evaluation, molds and yeasts were < 10 UFC/mL and the total coliforms (NPN/mL) < 3 until the third evaluation. No significant differences (P > 0.05) were founded on: pH. degree Brix and total sugars. Significant differences (P < 0.05) were founded in vitamin C and total carotenoids content. Sensorial analysis did not show significant differences between formulations for the smell and flavor attributes, when the color was discriminate during the evaluations. The formulation I (without acid ascorbic) had more preference due its color. In conclusion, the nectars showed useful life of 14-21 days under refrigeration condition storage due to the adequate physicochemical and microbiological quality of the product.     

Nutritional composition and vitamin C stability in stored camu-camu (Myrciaria dubia) pulp

Camu-camu (Myrciaria dubia), a native fruit of the Amazon region, is one of the richest sources of vitamin C (2.4 to 3.0 g/100 g in the pulp) found in Brazil. The purpose of this work was the physical-chemical characterization of some nutrients and the valuation of vitamin C stability in stored camu-camu pulp, produced by the Agronomic Institute of Paraná (IAPAR), Paraná State, Brazil. The vitamin C determination was made by titration with potassium iodate. The fruit produced in Paraná State, presented a lower content of vitamin C than the one native of the amazon region, possibly due to the different development conditions of the plant, and consequently of the fruit, as well as the climatic variation, the humidity and the characteristics of the soil. Regarding the vitamin C stability in stored (-18 degrees C) camu-camu pulp, a considerable decrease in its concentration until the 28th day was observed lost 23% (from 1.57 to 1.21 g/100 g), staying approximately the same until the end of the experiment. After 335 days of storage, the content found was of approximately 1.16 g/100 g of pulp, the ascorbic acid losses amounted to 26%. This content was still higher than the one found for most fruits that are good sources of this vitamin.     

Correlation between antioxidant activity and bioactive compounds of açaí (Euterpe oleracea Mart) comercial pulps

The purpose of this work was to analyze commercial a?aí pulp and to correlate the contribution of vitamin C, total carotenoids and phenolic compounds with the antioxidant activity of there products besides the examination of the standard related to the quality of the obtained products. Analysis were made with regard to pH, acidity total, soluble solids, sugars, color, water activity, vitamin C, total anthocyanins, total carotenoids, antioxidant activity and phenolic compounds. All parameters analyzed showed significative difference among the marks not added with preservatives and sucrose. The a?aí fruit can be considered a fair source of vitamin C and good source of natural antioxidants. In regard to the correlation with the antioxidant activity only the total anthocyanins and the total carotenoids presented positive and significative correlation.     

Stability of anthocyanins in pasteurized juice of blackberry ((Rubus glaucus benth

In this research the chemical stability of total anthocyanins in three pasteurized juices elaborated from 12% of blackberry (Rubus glaucus Benth) pulp, and addition of ascorbic acid (Formulation A: 0.1%, Formulation B: 0.05% and Formulation C: 0.01%), was evaluated by means of absorption visible spectra (400-580 nm). Physicol-chemical characterization (acidity, soluble solids content in degree Brix, pH), and count of mesophilic microorganism, fungi, yeasts, fecal coliforms (PMN/mL) and Escherichia coli, were evaluated. Sensorial parameters (color, smell, flavor) were investigated by means of un-trained panel using a hedonic scale (Fridman, P < 0.05). The study was performed during storage for 9 days. The total anthocyanins were reported as pelargonidin-3-glycoside g/L, and no significant differences were founded among the evaluated in each formulation during storage (P > 0.05). Bactocromic effect due to oxidation as not observed. Acidity (6.0-7.2 mL NaOH 0.079 N), soluble solids content (9.0-9.8 degrees Brix) and pH (3.4) did not show significant differences (P > 0.05). The microbiological evaluation showed minimum values for pasturized products (fungi CFU/mL < 10, yeast CFU/mL < 10, fecal coliforms CFU/mL < 10 and mesophilic microorganism CFU/mL between 120-140 on first day in storage). Sensorial analysis did not show significant differences (Fridman, P > 0.05).     

pH值对重组人源抗狂犬病病毒单克隆抗体稳定性的影响

目的研究pH值对重组人源抗狂犬病病毒单克隆抗体NM57稳定性的影响。方法将NM57原液的pH值分别调节为4.0、5.0、6.0、7.0和8.0,分别置于4和40℃保存,于0、2、4、6周取样,观察其外观的变化,并检测其SDS-PAGE及SEC-HPLC纯度。中试规模制备NM57制剂(200IU/ml,pH6.0),4℃放置3、6、9、12、18和24个月,取样观察其外观的变化,SEC-HPLC检测样品纯度,快速荧光灶抑制试验(RFFIT)检测样品中和活性。结果在观察期内,所有样品的外观均保持澄清透明。不同pH值的NM57原液4℃放置6周,纯度无明显变化;40℃放置的不同pH值的NM57原液样品纯度变化有明显差异,NM57(5.0)和NM57(6.0)样品相对稳定。中试规模制备的6批NM57制剂4℃放置24个月,其纯度及中和活性均保持稳定。结论NM57原液在甘氨酸-组氨酸缓冲系统中,pH6.0条件下比较稳定,NM57(pH6.0)制剂长期稳定性良好。     

Study of the reineta protein modifications (Brama australis), put under freezing and storage to -18 degrees C and -30 degrees C

The objective of the present work was to study functional and thermal properties of reineta (Brama australis) frozen meat, analysed by water retention capacity (WRC), gel forming capacity (GFC), texture, emulsifying capacity and differential scanning calorimetry (DSC). For this study, reineta fillets were obtained and extracted by the same conditions, and cutted, packaged, frozen and stored at -18 degrees C and -30 degrees C for 7 months. The results obtained, showed that there were no signifficant differences in the responses to thermal treatment for all the specimens. For samples frozen at -18 degrees C and -30 degrees C, the protein contents were 23.5 + 0.0 and 25.4 + 1.0%, respectively. The WRC values were 0.45 + 0.1 and 1.59 +/- 0.0 g water/g protein, respectively. The gel forming capacity was only present in the fresh samples, whereas the frozen stored ones only form protein aggregates. The emulsifying capacity was between 960 and 1400 g oil / g protein, and the storage time increased this value. The miosin denaturation temperature (Td) and denaturation enthalpy (?H), obtained by DSC, fluctuated between 39.2 +/- 0.5 to 44.8 +/- 0.8 degrees C and 1.12 +/- 0.3 to 0.52 +/- 0.2 J/g, respectively. The actina values were between 71.0 +/- 0.6 to 75.3 +/- 0.5 degrees C and between 0.5 +/- 0.1 to 0.7 +/- 0.1 J/g. Cooperativity decreased as the storage time increased. This is showing a certain degree of protein displacement. The values found by thermal analyses showed a direct relationship with the functional properties, both decreasing with storage time.     

Effect of Lipase Activity and Specificity on the DAG Content of Olive Oil from the Shodoshima-Produced Olive Fruits

Olive oils have a higher relative diacylglycerol (DAG) content than other plant oils. The lipase in olive fruits is involved in DAG production and is directly related to the acidity of the olive oil. However, the lipase activity and positional selectivity have not been clarified. To investigate the properties of olive fruit lipase, olive fruits of the Mission variety harvested during mid-December of 2005 on Shodoshima Island (Japan) were stored at 20, 30 or 40 °C for 4 weeks. Changes in the acidity and acylglycerol content of the oils extracted from the stored fruits were analyzed. The acidity and DAG content of the olive oils increased due to triacylglycerol (TAG) hydrolysis during storage. sn-1,2-DAGs preferentially increased during the early stages of storage, indicating that the olive fruit lipase is enantioselective for the sn-3 position, while non-enzymatic isomerization of sn-1,2-DAGs was observed throughout the entire duration of storage. Kinetic analysis revealed that the enantioselectivity of olive fruit lipase for the sn-3 position was approximately four times greater than for the sn-1 position. The lipase was gradually inactivated at temperatures of 30 °C or higher, and the ratios of the rate constant for inactivation to TAG hydrolysis at the sn-3 position was 0.2, 13, and 23 at 20, 30, and 40 °C, respectively.     

阿维菌素在梨贮藏中的降解动态

研究了阿维菌素在梨果实中的分布及其在梨贮藏中的降解动态。阿维菌素残留用乙腈提取，C18固相萃取柱净化，用反相色谱柱分离、荧光检测器检测。阿维菌素添加回收率为85．6％～101．6％，相对标准偏差为1．0％～7．1％。最低检出限为0．002mg／kg。梨皮中阿维菌素的半衰期约为13．8d，梨肉中阿维菌素的半衰期约为1．5d，梨皮中阿维菌素的含量是梨肉中的200倍。     

Physical and chemical stability of Refractance Window®–dried mango (Philippine ‘Carabao’ var.) powder during storage

The effect of packaging atmosphere, storage temperature, and time on the physical and chemical stability of Refractance Window® (RW)-dried mango powder was evaluated over a period of 12 months. RW-dried mango powder with a moisture content of 0.037?±?0.001?kg water/kg dry solids was stored at 5, 22 and 45°C for 12 months using air or nitrogen flush packaging. Headspace gas composition in the package, moisture content, color, ascorbic acid (AA), β-carotene, and microstructures of powder was measured at months 0, 6, and 12. The mango powder stored at 45°C suffered discoloration and ascorbic acid and β-carotene degradation after 6 and 12 months of storage in both air packaging and nitrogen flush packaging, while powder stored at 5 and 22°C had reduced nutrient degradation and preserved color of mango powder for both packaging conditions. Replacing the air inside the package with nitrogen was effective in preserving AA in mango powder stored at 22 and 5°C. Nitrogen flushing also reduced the percentage loss of β-carotene after 6 months, but no significant difference was found after 12 months. The microstructure of mango powder stored at 5 and 22°C was preserved after 6 and 12 months. Regardless of the packaging technique applied, the powder particles inside the package formed a single lump when stored at 45°C. The microstructures of mango powder at different storage conditions confirmed these results. Nitrogen flush packaging of mango powder is recommended to minimize degradation during long-term storage.     

Sensory and chemical evaluation of stored oil-roasted,high oleic nonoil sunflower kernels

High oleic acid (HOA) and high linoleic acid (HLA) nonoil (confectionery) sunflower kernels were oil-roasted at 180 C and then stored at 27 C for up to 26 weeks (wk). At two- and/or four-wk intervals, samples were removed for chemical and sensory analyses. Fatty acid composition of the oils extracted from the roasted kernels were as follows: HOA — 16:0, 3.6%; 18:0, 3.3%; 18:1, 68.3%, and 18:2, 23.7%; regular HLA — 16:0, 5.0%; 18:0, 3.5%; 18:1, 29.0%, and 18:2, 62.6%. Hunter L and a values and hue angle for HOA and HLA kernels changed significantly (P<0.01) during 26 wk storage. Hunter a values for HLA did not change significantly but Hunter a values for HOA decreased significantly (P<0.01) during storage. Free fatty acids (FFA) of both the HLA and the HOA kernels increased significantly (P<0.01) beginning at 16 wk storage. In addition, the FFA from HLA kernels were significantly higher (P<0.01) than those from HOA kernels. Both types of stored, roasted kernels showed significant differences in sensory scores from the control samples (regular HLA type held at −35 C) beginning at four wk but rate of change throughout storage was similar for both kernel types. Sensory data were combined with objective parameters to analyze the multivariate data set by VARCLUS. Four clusters of attributes were extracted that explained 71.9% of the variation in the data. The data show there was a significant increase in off-flavor for both HLA and HOA kernels but no significant difference between the two types of kernels. Changes in the color of the sunflower kernels during storage evidently were not related to flavor quality.     

Stabilization of refined olive oil by enrichment with chlorophyll pigments extracted from Chemlali olive leaves

This paper presents the first investigation on the effect of enrichment refined olive oil by chlorophyll pigment extracted from Chemlali olive leaves during storage (6 months). The changes that occurred in the quality indices, fatty acids, sterol, and phenolic content were investigated during the storage of refined olive oil under RT (20°C) and accelerated conditions (50°C) in the dark. Additionally, the pigments (chlorophyll and carotene) changes during 6 months of oil storage were evaluated. At the end of the storage, more than 90% of chlorophyll pigments decomposed in all samples, while, carotene pigment loss was lower showing up to 60 and 85% loss for oil stored at 20 and 50°C, respectively, at the end of storage. The reduction of total phenolic compounds exhibited similar degradation profiles, being reduced by 5% and up to 60% for the enriched refined olive oil stored at 20 and 50°C in 6 months, respectively. In the fatty acid composition, an increase in oleic acid and a decrease in linoleic and linolenic acids were less significant in enriched than non‐enriched refined olive oil. On the other hand, sterol composition was less affected by storage in enriched oil samples. However, the sterol concentration of the oil samples showed an increase in β‐sitosterol, 24‐methylene cholesterol, stigmasterol, and a decrease in cholesterol, Δ5, 24‐stigmastadienol percentage at the end of storage. Based on the Rancimat method, the oils with added leaf pigment extract had the lowest peroxide value and the highest stability. After 6 months of storage, the oxidative resistance of refined olive oil fell to 0.2 and to zero for enriched refined olive oil stored at 20 and 50°C, respectively.     

Quantification of carbonyl compounds in oxidized low-linolenate,high-stearate and common soybean oils

The carbonyl compounds in five oxidized soybean oils (SBO) of various fatty acid compositions were determined. Three were from common normal soybean varieties, and two were from lines developed from new mutant varieties. One mutant line had a linolenate (18:3) content of 3.5% (A5), and one had a stearate (18:0) content of 24% (A6). SBO were stored at 28 C and 60 C. Trichlorophenylhydrazones (TCPH) of carbonyls formed during oxidation were quantified and tentatively identified by gas chromatography. The storage temperature and the composition of the oils affected the types and amounts of volatiles produced. Hexanal was the major volatile in the oils in both storage tests. After 60 C storage, 2- and/or 3-hexenal was present only in the oil with the highest 18:3 content (BSR 101, 18:3=9%). The amounts of the carbonyls formed in A5 were 2 to 5 times less than the amounts formed in BSR 101. The amounts of many of the carbonyls were converted into relative flavor potency by using reported data. Hexanal was the major contributor to flavor. After storage at 28 C, 2- and/or 3-hexenal was the second most intense flavor compound regardless of the 18:3 content of the oil. The amount of a compound and the threshold value did not always predict its flavor importance according to the flavor potency data.     

A Vacuum Drying Model for Mango Pulp

Vacuum drying of mango pulp at varying conditions of pulp thickness (2, 3, and 4 mm) and vacuum chamber plate temperature (65, 70, and 75°C) was carried out under 30-50 mm of mercury absolute pressure. A model based on moisture diffusivity was found to give close prediction to moisture content of the pulp at different times of drying with correlation coefficient varying between 0.98-0.99 for pure mango pulp and pulp with ingredients. Color change of reconstituted pulp made from mango powder was found to depend more on pulp thickness than plate temperature. For getting low color change vacuum drying should be carried at maximum pulp thickness of 2.6 mm and vacuum chamber plate temperature of 72.3°C.     

Edible coating effects on the sensory quality of green bell pepper fruits (Capsicum annuum L.) during storage

Edible coating based on carboxymethyl cellulose (CMC) and stearic acid were applied on green bell peppers (Capsicum annuum L.) samples in order to investigate its effects as protecting agent to enhance natural characteristics of products. Samples were submitted to three lots according to: (T1) uncoated; (T2) coated in lower part of the stem; (T3) coated all over the surface (T3). During storage at 5 +/- 1 degrees C, for 28 days, sensory quality and weight loss were evaluated. Sensory characteristics such as color, appearance and firmness were controlled using a composite scoring test. At the end of the study, T3 treatment showed better sensory stability than T1 (p < 0.05), none significant changes between T2 and T3 were found. The coated samples showed less firmness deterioration compared with control samples. The color was the attribute that changed less, without significant difference between treatments (p > 0.05).     

Suitability of hydrogenated soybean oils for prefrying of deep-frozen french fries

The suitability of hydrogenated soybean oils (fats) for prefrying of deep-frozen french fries has been investigated in a frying and storage experiment with five hydrogenated oils, of which four were commercially available and one was experimentally prepared. Three frying oils were hydrogenated soybean fats (0% C18:2 and C18:3), one was a partly hydrogenated soybean oil (25% C18:2; 0% C18:3) and one a hydrogenated palm fat (0% C18:2). An intermittent frying and heating procedure was used. Prefried french fries were stored deep-frozen at ?18 to ?20 C for a period of one year. Although differences in hydrolysis and oxidation during frying were observed, the five hydrogenated frying oils were quite stable. During the storage period, hydrolytic and oxidative changes in the oil phase of prefried french fries were not detected, regardless of the frying oil used. Only slight changes in sensory quality could be detected in all french fry samples stored for one year at ?18 to ?20 C. Some differences in odor and taste of finish-fried french fries observed initially were not observed after prolonged storage. Thus, it has been concluded that hydrogenated soybean oils, including a partly hydrogenated one, are suitable for prefrying french fries and for long-term storage of deep-frozen products.     

Effect of packing material and temperature of storage on the quality of maize tortilla]

Three packaging materials (tortilla-packing paper, low-density polyethylene and high density polyethylene) were used to evaluate tortilla shelf-life at two different temperatures (-10 degrees C and 5 degrees C). Tortilla quality changes upon storage were evaluated by measuring pH, total moisture, texture (puncture and cutting resistance) and sensory characteristics. Results were analyzed by means of covariance analysis and slope contrast between treatments with a 0.05 level of significance. At -10 degrees C, the quality of tortillas did not change significantly during 11 days of storage, and the influence of the packaging material was negligible. Tortilla kept at 5 degrees C in high or low-density polyethylenes, had significantly better quality than the paper-packaged product. Textural changes were best shown by the Instron puncture resistance test than by the cutting resistance test. At 5 degrees C, packaged tortillas had a microbiologically stable level for up to seven days, while that at -10 degrees C significantly improved over the storage period.     

Preparation and nutritional characteristics of a hydrolysate from pepitona (Arca zebra)

Two soluble products resulting from the hydrolysis of pepitona (Arca zebra) were prepared as flour. Papain at its optimum hydrolysis conditions, previously established, was the enzyme used (40 degrees C for two hours at a pH of 7 in the proportion of 0.3% weight/enzyme/100 g meat). The hydrolysate obtained was then subjected to two different dehydration techniques: drum drying at 121 degrees C and 18 seconds retention, and spray drying at 101 degrees C and 40 psi pressure. The products were then stored for a five-month period at a temperature of 25 degrees C +/- 2 degrees C, time during which chemical determinations were performed in both hydrolysates. Findings showed that the time of storage does exert a significant effect of deterioration on the products. The greater and more significant quality losses occur during the first two months. The dehydration techniques used also affect significantly the soluble nitrogen content, and non-protein nitrogen and soluble solids content, as well as color of pepitona hydrolysates. Spray-drying dehydration technique does not have a significant deteriorating effect. Biological studies undertaken demonstrated that the quality of both hydrolysates is satisfactory from the nutritional and amino acid composition points of view. A protein efficiency ratio (PER) of 2.27 and 2.29 was determined for the hydrolysate dehydrated by drum drier and for the dehydrated by spray drier, respectively. With regard to amino acid composition, both had satisfactory levels of essential amino acids, with a lysine content of 6.9 g/100 g protein for the hydrolysate dehydrated by drum drying, and 8.6 g/100 g protein for the other hydrolysate dehydrated by spray drying.     

Quality of oils from olives stored under controlled atmosphere

Olive (Olea europaea cv. “Picual”) fruits were stored under five different storage conditions (°C/%CO₂/%O₂; ambient; 5:0:21; 5:3:20; 5:3:5; and 5:<1:5) to determine their influence on the chemical and sensorial quality of oil extracted from the olives at the end of the storage period. Results showed that storage of fruits at 5°C prevented the fast alteration that is produced in oils extracted from fruits stored at ambient temperatures. The use of controlled atmosphere at 5°C with 3% CO₂ and/or 5% O₂ did not present clear advantages on acidity, peroxide value, K₂₇₀ and K₂₃₂ coefficients, stability and sensorial quality. Cooling of fruit keeps physical, chemical and sensorial characteristics of oil below maximum established values for the period of time assayed (60 d).