scholarly journals Honey physicochemical properties of three species of the brazilian Melipona

2012 ◽  
Vol 84 (3) ◽  
pp. 605-608 ◽  
Author(s):  
Lorena G.A. Lage ◽  
Lívia L. Coelho ◽  
Helder C. Resende ◽  
Mara G. Tavares ◽  
Lucio A.O. Campos ◽  
...  
Keyword(s):  
Water Activity ◽  
Ph Value ◽  
Soluble Solids ◽  
Ph Values ◽  
Microbial Development ◽  
Potential Factors ◽  
Melipona Species ◽  
High Level ◽  
Favorable Conditions ◽  
And Storage

Physicochemical analyses were carried out to evaluate 27 samples of honeys from three species of the Brazilian genus Melipona (M. capixaba, M. rufiventris and M. mondury) from Espírito Santo and Minas Gerais States. The parameters water activity (Aw), percentage of soluble solids (Brix %), pH, acidity (meq/Kg) and moisture (%) were evaluated. The honey characteristics obtained from these samples were very similar to the ones from other Melipona species. However, regarding the honey from Apis (honey bee), only the pH values were similar. The low pH value and the high acidity detected in Melipona honey are potential factors for increasing the honey shelf life because they do not provide favorable conditions for the microbial development. On the other hand, the high level of water activity favors the growth of microorganisms, especially yeast, which demands a more careful handled and storage. The observed differences between Melipona and Apis honey reinforce the need for specific quality settings for stingless bee honey.

scholarly journals Stability of Kiwi Varieties of ‘Hayward’ in Powder During Storage

2020 ◽  
Vol 8 (2) ◽  
pp. 150
Author(s):  
Inacia Dos Santos Moreira ◽  
Jacinete Pereira Lima ◽  
Deise Souza de Castro ◽  
Wilton Pereira da Silva ◽  
Josivanda Palmeira Gomes ◽  
...  
Keyword(s):  
Water Activity ◽  
Bioactive Compounds ◽  
Titratable Acidity ◽  
Physicochemical Characteristics ◽  
Soluble Solids ◽  
Total Chlorophyll ◽  
Lower Content ◽  
Total Water ◽  
Ph Values ◽  
The Stability

For the preservation of products obtained by dehydration, it is necessary to evaluate their physicochemical characteristics during storage. It was proposed, in the present study, to evaluate the stability of the kiwi cv. ‘Hayward’ powder, obtained at temperatures of 60 and 70 °C during its storage in laminated packages under controlled conditions of temperature (25 ºC) and relative humidity (75%) for 90 days. The parameter’s evaluated were: moisture content, ashes, soluble solids, titratable acidity (% citric acid), pH, water activity at 25 ºC, color for the parameters lightness (L*) and chromaticity (+a* red; -a* green; +b* yellow; and -b* blue), phenolic compounds, flavonoids, total chlorophyll and carotenoids. It was observed that, after the 90 days, for the powder obtained at 70 °C, the soluble solids and pH values were altered by the storage, which did not occur for the powder obtained at 60 °C. For both powders, the content of ash and bioactive compounds were not affected by storage. The parameter of lightness decreased in both powders. The powder obtained at 70 ºC proved to be better, showing lower content of moisture and total water activity, as well as the highest values of bioactive compounds.

Pemanfaatan Hasil Samping Fermentasi Belimbing Wuluh (Asam Sunti) dalam Pengolahan Ikan

2018 ◽  
Vol 3 (2) ◽  
pp. 351-356
Author(s):  
Weny Weny ◽  
Rasdiansyah Rasdiansyah ◽  
Novia Mehra Erfiza
Keyword(s):  
Soluble Protein ◽  
Room Temperature ◽  
Storage Time ◽  
Ph Value ◽  
Block Design ◽  
Total Acid ◽  
Soaking Time ◽  
Ph Values ◽  
Randomized Block Design ◽  
And Storage

Abstrak. Sampai saat ini belum ada penelitian lebih lanjut mengenai pemanfaatan hasil samping dari produk asam sunti. Tujuan penelitian ini untuk melihat pengaruh perendaman ikan di dalam air asam sunti dan penyimpanannya pada suhu ruang terhadap karakteristik ikan. Penelitian ini menggunakan Rancangan Acak Kelompok Faktorial dengan 2 faktor yaitu faktor waktu perendaman (W), yang terdiri dari 3 taraf (W1 : 30 detik, W2 : 5 menit, W3 : 10 menit) dan lama penyimpanan (S), yang terdiri dari 2 taraf (S1 : 0 jam, S2 : 2 jam). Hasil penelitian menunjukkan bahwa karakteristik air asam sunti pada uji pH memiliki rataan yaitu 1,27, total asam 49% dan total bakteri asam laktat  5,1×104 CFU/gram. Nilai pH ikan setelah direndam air asam sunti 5,22-5,65 dengan rataan 5,43 dan nilai protein terlarut berkisar antara 18,42-18,74% dengan rataan 18,74%.Dari penelitian didapatkan bahwa waktu perendaman (W) berpengaruh nyata (P≤0,05) terhadap nilai protein terlarut dari ikan namun berpengaruh tidak nyata (P0,05) terhadap nilai pH ikan, uji deskriptif aroma dan tekstur ikan. Lama penyimpanan (S) berpengaruh sangat nyata (P≤0,01) terhadap nilai pH ikan setelah perendaman namun berpengaruh tidak nyata (P0,05) terhadap uji deskriptif aroma dan tekstur ikan. Interaksi waktu perendaman dengan lama penyimpanan berpengaruh nyata (P≤0,05) terhadap nilai pH ikan namun berpengaruh tidak nyata terhadap uji deskriptif aroma dan tekstur ikan.Waktu perendaman ikan di dalam air asam sunti selama 10 menit dapat menghambat kenaikan pH ikan selama penyimpanan sampai 2 jam. Semakin lama perendaman ikan di dalam air asam sunti maka semakin tinggi protein terlarut dari ikan.  Abstrack. Therefore, this study was conducted to see the effect of soaking the fish in asam sunti water and its storage at room temperature on the characteristics of the fish. This study uses a randomized block design factorial with 2 factors: soaking time (W), consisting of 3 levels (W1: 30 seconds, W2: 5 minutes, W3: 10 minutes) and storage time (S), consisting of 2 levels ( S1: 0 hours, S2: 2 hours). The results showed pHof asam sunti water is 1.27,  total acid is 49% and lactic acid bacteria has  of  5.1 × 104 CFU / gram and the soaked fish has pH values ranged from 5.22 to 5.65 with the average of 5.43 and soluble protein values ranged from 18.42 to 18.74% with the average 18.74%.The results indicated that the soaking time (W) has effect significantly to the value of soluble protein (P≤0,05) of fish but iteffect not significantly (P 0.05) on pH value of fish, descriptive test the of aroma and texture of the fish. Storage time (S) effect significantly (P≤0,01) to pH value of fish after soaking but it effectnot significantly (P 0.05) to the descriptive test of  aroma and texture of the fish. Interaction withsoaking time and storage (WxS) effect significantly (P≤0,05) to pH value of fish but it effect to not significantly the descriptive test of aroma and texture of the fish.Soaking time the fish in water for 10 minutes sunti can inhibit increasing in the pH of the fish during storage up to 2 hours. The longer soaking time of the fish in the asam sunti water, the higher sunti acid soluble proteins from value.

scholarly journals Some Chemical Characteristics of Sucuk and Salami Samples Available at Retail in Adana

2017 ◽  
Vol 5 (11) ◽  
pp. 1307
Author(s):  
Hakan Benli
Keyword(s):  
Water Activity ◽  
Ph Value ◽  
Dietary Exposure ◽  
Chemical Characteristics ◽  
Local Markets ◽  
Moisture Contents ◽  
Ph Values ◽  
Retail Outlets ◽  
Residual Nitrite ◽  
Lower Variation

The aim of this study was to investigate some chemical characteristics and residual nitrite and nitrate levels of sucuk and salami samples collected from retail outlets of major supermarkets in Adana province. A total of 36 sucuk samples (12 brands; 7 national and 5 local producers) and 30 salami samples (10 brands; Macar salamis) were purchased from local markets. Sucuk and salami samples were analyzed for pH value, moisture content, water activity and nitrite and nitrate contents. The average pH values of sucuk samples ranged between 4.69 and 6.56 indicating a higher variation while the average pH values of salami samples ranged between 6.05 and 6.43. Likewise, the average moisture contents of sucuk samples were between 33.56% and 46.78% whereas the average moisture contents of salami samples ranged between 62.09% and 67.91% indicating a relatively lower variation. Water activity values of the sucuk samples were between 0.932 and 0.861 while the average aw values of the salami samples ranged between 0.916 and 0.940. Among the sucuk samples analyzed in the present study mean nitrite and nitrate contents ranged from 58.65 mg/kg to 216.63 mg/kg and 34.86 mg/kg to 161.08 mg/kg, respectively. While relatively lower nitrite (14.30 mg/kg - 35.96 mg/kg) and no nitrate contents were observed in salami samples, the data indicated that a higher variation of both nitrite and nitrate contents were still present in sucuk samples in the local markets requiring more studies and inspections to lower the variation related to dietary exposure to nitrite and nitrite from these types of products.

Characteristics of the raw fruit, industrial pulp, and commercial jam elaborated with Spanish quince (Cydonia oblonga Miller)

2020 ◽  
pp. 623
Author(s):  
Esther Vidal Cascales ◽  
José María Ros García
Keyword(s):  
Antioxidant Activity ◽  
Phenolic Compounds ◽  
Vitamin C ◽  
Water Activity ◽  
Soluble Solids ◽  
Total Phenolic ◽  
Microbiological Analysis ◽  
Total Phenolic Compounds ◽  
And Storage

Quince fruit and two industrial derivates (pulp and jam) were characterized from physicochemical, nutritional and microbiological viewpoint. Quinces were collected at maturity (September) in Murcia (Spain). Quinces were converted at a processing factory in pulp (intermediate product) and, in the same factory, this pulp was transformed in jam. The pH, soluble solids, acidity, color, moisture, water activity, total phenolic compounds, antioxidant activity, vitamin C and flavonoids were measured for all samples, while for microbiological analysis was only used quince jam. There were significant differences among quince fruit, industrial pulp and commercial jam. Processing caused pH, moisture and water activity decrease, while soluble solids increase. Total phenolic compounds and antioxidant activity increased in the pulp and in the jam. The effect of cooking and storage was a decrease of vitamin C and flavonoids in the jam. Quince jam presented a total number of molds and yeasts lower than 2 log cfu/g. Although the production parameters affect to the quality of the quince jam, it is a sensory attractive food with healthy properties.

Behavior of Salmonella enteritidis During the Manufacture, Ripening, and Storage of Feta Cheese Made from Unpasteurized Ewe's Milk

1993 ◽  
Vol 56 (1) ◽  
pp. 25-28 ◽  
Author(s):  
C. PAPADOPOULOU ◽  
V. MAIPA ◽  
D. DIMITRIOU ◽  
C. PAPPAS ◽  
L. VOUTSINAS ◽  
...  
Keyword(s):  
Water Activity ◽  
Salmonella Enteritidis ◽  
Cheese Making ◽  
Ph Values ◽  
Standard Procedures ◽  
Feta Cheese ◽  
Ewe's Milk ◽  
And Storage

The ability of Salmonella enteritidis to grow during the Feta cheese-making process and to survive during ripening and storage of the cheese was investigated. Unpasteurized whole ewe's milk was inoculated to contain 106–107 CFU/ml of S. enteritidis and was processed into Feta cheese following standard procedures. All samples were examined for S. enteritidis both quantitatively and qualitatively, while moisture, fat, water activity, and pH values were also measured. S. enteritidis was enumerated in duplicate samples by surface plating on SS agar. Selected Salmonella colonies were identified biochemically and serologically. The enumerations have shown that S. enteritidis was entrapped in curd with the population increasing to a maximum during the First 48 h. Thereafter, the growth of S. enteritidis was inhibited and surviving cells persisted in the curd for up to 20 d.

STUDI KIMIA IKAN BANDENG (Chanos chanos Forskal) TANPA TULANG YANG DIKEMAS MENGGUNAKAN METODE KEMASAN BERBEDA PADA PENYIMPANAN SUHU DINGIN (5°C)

2020 ◽  
Vol 3 (2) ◽  
pp. 143
Author(s):  
Faisal Faisal ◽  
Andi Besse Patadjai ◽  
Muhammad Syukri Sadimantara
Keyword(s):  
Ph Value ◽  
Block Design ◽  
Vacuum Packaging ◽  
Diversity Analysis ◽  
Chemical Parameters ◽  
Chanos Chanos ◽  
Ph Values ◽  
Randomized Block Design ◽  
Significant Difference ◽  
And Storage

ABSTRACT         The aim of this study was to determine the chemical changes in boneless milkfish (Chanos chanos Forskal) with cold storage (5°C) until the 6th day. This study used a randomized block design (RBD) with 3 treatments; milkfish samples without packaging (C1), non-vacuum packaging (C2), and vacuum packaging (C3) and performed 3 times. Chemical parameters include pH, TVB, and TMA. The data obtained were analyzed using diversity analysis (ANOVA) and if a significant difference found in treatments then the DMRT test was continued. The results showed a significant difference in the TVB value 0-day storage, but in the pH and TMA values, there were no significant differences. The results of research on the storage of the 6th day showed a significant difference to the value of TVB and TMA, but at pH value, there was no significant difference. The results showed that the pH values of 0 and 6 days remained stable in the neutral range (6.3-6.8). TVB and TMA values for each treatment and storage are below tolerant limits. The highest values in TVB and TMA treatment without packaging on the 6th day (C1) were 19.39 mgN/100 gr and 3.32 mg/100 gr, respectively.Keywords: chemical compound, packaging, storage, thorns leave milkfishABSTRAKTujuan dari penelitian ini adalah untuk mengetahui perubahan kimia ikan bandeng tanpa tulang (Chanos chanos Forskal) pada penyimpanan suhu dingin (5°) pada awal penyimpanan sampai hari ke-6. Penelitian ini menggunakan rancangan acak kelompok (RAK) dengan 3 perlakuan yaitu sampel ikan bandeng tanpa kemasan (C1), kemasan nonvakum (C2), dan kemasan vakum (C3) dan dilakukan 3 kali ulangan. Perubahan kimia yang diukur meliputi pH, TVB, dan TMA. Data yang diperoleh dari uji kimia dianalisis menggunakan analisis keragaman (ANOVA) untuk mengetahui ada tidaknya perbedaan pada setiap perlakuan dan dilanjutkan uji DMRT jika didapatkan perbedaan yang signifikan. Hasil penelitian menunujukkan adanya perbedaan signifikan pada penyimpanan hari ke-0 terhadap nilai TVB, tetapi pada nilai pH dan TMA tidak terdapat perbedaan signifikan. Hasil penelitian pada penyimpanan hari ke-6 menunujukkan adanya perbedaan signifikan terhadap nilai TVB dan TMA, tetapi pada nilai pH tidak terdapat perbedaan signifikan. Hasil menunjukkan bahwa nilai pH hari ke-0 dan ke-6 nilai rata-rata pH tetap stabil di kisaran netral (6,3-6,8). Nilai TVB dan TMA pada setiap perlakuan dan penyimpanan dibawah batas tolerir. Nilai tertinggi pada TVB dan TMA pada perlakuan tanpa kemasan hari ke-6 (C1) masing-masing 19,39 mgN/100 gr dan 3,32mgN/100 gr.Kata kunci: Ikan bandeng tanpa tulang, kandungan kimia, kemasan, penyimpanan

scholarly journals Effects of variety and maturity stage of coconut on physicochemical and sensory characteristics of powdered coconut drink

2020 ◽  
pp. 43-51
Author(s):  
Jeallyza Muthia Azra ◽  
Budi Setiawan ◽  
Zuraidah Nasution ◽  
Ahmad Sulaeman
Keyword(s):  
Water Activity ◽  
Freeze Drying ◽  
Ph Value ◽  
Titratable Acidity ◽  
Nutrient Content ◽  
Biologically Active ◽  
Sensory Characteristics ◽  
Soluble Solids ◽  
Maturity Stage ◽  
Maturity Stages

Introduction. Coconut water is rich in nutrients and biologically-active compounds. However, it has a short shelf life that can be prolonged by freeze drying. The purpose of this study was to analyze the physicochemical and sensory characteristics of fresh and powdered coconut drinks. Study objects and methods. The experiments included eight samples, namely fresh and powdered coconut drinks obtained from coconuts of different varieties (tall and hybrid) and maturity stages (4 and 6 m.o.). The samples were analyzed for nutrient content (ash, protein, fat, total carbohydrate, and fibre), physicochemical properties (titratable acidity, pH, viscosity, total soluble solids, turbidity, water activity, and browning index), and sensory characteristics (color, aroma, taste, texture, and overall acceptance). Results and discussion. The results obtained showed that there were significant differences among the coconut drinks of different varieties and maturity stages. They differed in nutrient content, pH value, titratable acidity, viscosity, and water activity. Meanwhile, the aroma, taste, and overall acceptance scores of all the samples were not significantly different. The powdered drink from 6 m.o. hybrid coconut was selected as the optimal sample due to its good sensory and physicochemical attributes. These attributes were similar to those of the fresh coconut drink. Conclusion. The powdered drink from 6 m.o. hybrid coconut obtained by freeze drying could be considered as an alternative healthy drink with good quality characteristics.

scholarly journals The Influence Mechanism of Temperature and Storage Period on Polarization Properties of Poly (Vinylidene Fluoride–Trifluoroethylene) Ultrathin Films

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 301
Author(s):  
Xingjia Li ◽  
Zhi Shi ◽  
Xiuli Zhang ◽  
Xiangjian Meng ◽  
Zhiqiang Huang ◽  
...  
Keyword(s):  
Ultrathin Films ◽  
Remanent Polarization ◽  
Vinylidene Fluoride ◽  
Storage Period ◽  
Testing Temperature ◽  
Fatigue Properties ◽  
Inhibition Mechanism ◽  
Poly Vinylidene Fluoride ◽  
High Level ◽  
And Storage

The effect of testing temperature and storage period on the polarization fatigue properties of poly (vinylidene fluoride-trifluoroethylene) (P(VDF–TrFE)) ultrathin film devices were investigated. The experimental results show that, even after stored in air for 150 days, the relative remanent polarization (Pr/Pr(0)) of P(VDF–TrFE) of ultrathin films can keep at a relatively high level of 0.80 at 25 °C and 0.70 at 60 °C. To account for this result, a hydrogen fluoride (HF) formation inhibition mechanism was proposed, which correlated the testing temperature and the storage period with the microstructure of P(VDF–TrFE) molecular chain. Moreover, a theoretical model was constructed to describe the polarization fatigue evolution of P(VDF–TrFE) samples.

scholarly journals Bonding of Selected Hardwoods with PVAc Adhesive

2020 ◽  
Vol 11 (1) ◽  
pp. 67
Author(s):  
Ján Iždinský ◽  
Ladislav Reinprecht ◽  
Ján Sedliačik ◽  
Jozef Kúdela ◽  
Viera Kučerová
Keyword(s):  
Adhesion Strength ◽  
Cold Water ◽  
Ph Value ◽  
Water Extract ◽  
Solid Wood ◽  
Contact Angles ◽  
Water Contact ◽  
Ph Values ◽  
Positive Tendency ◽  
The Impact

The bonding of wood with assembly adhesives is crucial for manufacturing wood composites, such as solid wood panels, glulam, furniture parts, and sport and musical instruments. This work investigates 13 hardwoods—bangkirai, beech, black locust, bubinga, ipé, iroko, maçaranduba, meranti, oak, palisander, sapelli, wengé and zebrano—and analyzes the impact of their selected structural and physical characteristics (e.g., the density, cold water extract, pH value, roughness, and wettability) on the adhesion strength with the polyvinyl acetate (PVAc) adhesive Multibond SK8. The adhesion strength of the bonded hardwoods, determined by the standard EN 205, ranged in the dry state from 9.5 MPa to 17.2 MPa, from 0.6 MPa to 2.6 MPa in the wet state, and from 8.5 MPa to 19.2 MPa in the reconditioned state. The adhesion strength in the dry state of the bonded hardwoods was not influenced by their cold water extracts, pH values, or roughness parallel with the grain. On the contrary, the adhesion strength was significantly with positive tendency influenced by their higher densities, lower roughness parameters perpendicular to the grain, and lower water contact angles.

scholarly journals Microstructure and Properties of Self-Assembly Graphene Microcapsules: Effect of the pH Value

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 587 ◽  
Author(s):  
Yan-Dong Guo ◽  
Jun-Feng Su ◽  
Ru Mu ◽  
Xin-Yu Wang ◽  
Xiao-Long Zhang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Chemical Engineering ◽  
Ph Value ◽  
Liquid Paraffin ◽  
Energy Dispersive Spectrometer ◽  
Core Material ◽  
Microstructure And Properties ◽  
Ph Values

Graphene has attracted attention in the material field of functional microcapsules because of its excellent characteristics. The content and state of graphene in shells are critical for the properties of microcapsules, which are greatly affected by the charge adsorption equilibrium. The aim of this work was to investigate the effect of pH value on the microstructure and properties of self-assembly graphene microcapsules in regard to chemical engineering. Microcapsule samples were prepared containing liquid paraffin by a self-assembly polymerization method with graphene/organic hybrid shells. The morphology, average size and shell thickness parameters were investigated for five microcapsule samples fabricated under pH values of 3, 4, 5, 6 and 7. The existence and state of graphene in dry microcapsule samples were analyzed by using methods of scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Fourier Transform Infrared Spectoscopy (FT-IR) and Energy Dispersive Spectrometer (EDS) were applied to analyze the graphene content in shells. These results proved that graphene had existed in shells and the pH values greatly influenced the graphene deposition on shells. It was found that the microcapsule sample fabricated under pH = 5 experienced the largest graphene deposited on shells with the help of macromolecules entanglement and electrostatic adherence. This microcapsules sample had enhanced thermal stability and larger thermal conductivity because of additional graphene in shells. Nanoindentation tests showed this sample had the capability of deforming resistance under pressure coming from the composite structure of graphene/polymer structure. Moreover, more graphene decreased the penetrability of core material out of microcapsule shells.

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