High Total Solids Content Research Articles

Untangling the effect of solids content on thermal-alkali pre-treatment and anaerobic digestion of sludge

Total solids (TS) content is critical for thermal hydrolysis and anaerobic digestion (AD) performance, but its role in thermal-alkaline pre-treatment (TAP) is unclear. Therefore, this study aimed to reveal the key role of TS content in TAP and AD of waste activated sludge. The results showed that the optimum TS content of TAP (at 90 °C for 1 h, pH = 10) was 8 %. Sludge disintegration and methane production increased from 19.7 ± 2.2 % to 34.3 ± 2.9 % and from 167.4 ± 4.2 to 246.0 ± 6.2 mL/g volatile solids, respectively, when TS content were increased from 2 % to 8 %. A high TS content will likely promote sludge disintegration since it will reduce heat loss and improve heating efficiency. Additionally, increasing TS content from 2 % to 10 % minimized the production of intracellular reactive oxygen species by 30.4 ± 0.7 % and increased cell viability by 11.5 ± 2.6 %. In contrast, excessive TS content (i.e., ≥10 %) deteriorated the fluidity of sludge, which prevents it from disintegration. Once TS reached 10 %, the accumulation of ammonia nitrogen and volatile fatty acids reached 812.7 ± 27.4 and 1932.0 ± 5.3 mg/L, respectively, which reduced the activity of acidulase and coenzyme F420 and shifted the archaeal community from acetylotrophic to hydrogenotrophic methanogens. This article provides new insights into the TS content in TAP and AD technology.

Understanding the mechanisms behind enhanced anaerobic digestion of corn straw by humic acids

Humic acids (HAs) are abundant on earth, yet their effects on anaerobic digestion (AD) of cellulosic substrate are not fully uncovered. The effects of HAs on AD of corn straw and the mechanisms behind were analyzed in this study. Results showed that the effects of HAs on methane yield were closely related to the total solids (TS) content. At relative high TS content of 5.0%, HAs benefited AD process by increasing 13.8% of methane yield, accelerating methane production rate by 43% and shortening lag phase time by 37.5%. Microbial community analysis indicated that HAs increased the relative abundance of syntrophic bacteria (Syntrophomonadaceae and Synergistaceae), facilitating the degradation of volatile fatty acids. HAs might act as electron shuttles to directly transfer electrons to hydrogenotrophic methanogens for CO2 reduction to CH4. This study provides a simple and efficient strategy to facilitate the AD of cellulosic substrate by HAs addition.

Performance evaluation of an industrial ceramic nanofiltration unit for wastewater treatment in oil production

An industrial ceramic nanofiltration membrane (pore size 0.9 nm) was tested in a Canadian oil field for more than 12,500 h to treat wastewater directly from daily operations, without any type of pre-treatment. This wastewater contained a high content of total suspended solids (13 to 510 mg/kg), and total organic carbon (31 to 134 mg/kg). The membrane unit was operated at different transmembrane pressure (TMP) set points (4–16 bar) and recovery set points (40–80%). The data show that ion and compound rejection depend strongly on a combination of both TMP and recovery, with the largest rejection occurring at low recovery values and high TMP values. Two mechanisms were responsible for rejection: sieving, which mostly impacted compound rejection, and electrostatic phenomena that impacted ion rejection. It is shown that ion rejection depends linearly on charge density of the ion. Ion rejection was measured as high as 85% and compounds (such as TSS) were rejected as high as 100%. The specific flux varied between 1–10 L/(m2.h.bar). Results from this field testing indicate the possibility of using these types of ceramic membranes for oil field wastewater treatment.

Preparation and characterization of natamycin-incorporated agar film and its application on preservation of strawberries

This study investigated the preparation and characterization of Natamycin-incorporated agar film and its antimicrobial effect on preserve quality of fresh strawberries. Natamycin-incorporated agar films were prepared by solvent casting method and characterized in mechanical, optical, water swelling, and barrier properties. Antimicrobial activity of the films and their preservative effects on strawberries stored at 4 °C and 20 °C were also assessed. As natamycin amount increased (0%, 0.33%, 0.66%, 0.99%, 1.33%, w/w of dry film), the antimicrobial activity of the film increased with inhibition zone of Aspergillus niger and Saccharomyces cerevisiae from 0 cm to approximate 28 cm, while there was no significant effect on water vapor permeability and swelling degree. On the other hand, with the increase of natamycin, tensile strength of the film declined (from 17.61 to 14.94 MPa), while oxygen permeability enhanced from 0.161 to 0.585 × 10−15 cm3 cm/cm2 s Pa. Furthermore, the natamycin can be released quickly from antimicrobial films within 2 days under aqueous solution in accordance with fick’s law. Along with the addition of natamycin, light transmittance of antimicrobial films trends to decrease whereas the haze and total color difference of film increase significantly. Compared to control group, fungal colony number of strawberry packaged in antimicrobial film was reduced by 0.51 and 1.05 log cfu g−1 at 4 °C and 20 °C, respectively. The strawberries packaged by antimicrobial film retained high total soluble solid content with higher hardness of 61.89% and 54.47% at 4 °C and 20 °C, respectively at the end of storage. Moreover, strawberries packaged with the natamycin-incorporated film showed lower rate of water loss during storage (1.43% and 7.66% at 4 °C and 20 °C, respectively). The obtained results indicate that natamycin-incorporated agar film could be used as environment-friendly packaging alternative to preserve perishable fresh produce and extend their shelf lives by means of antimicrobial activity and other merits.

Analysis of mechanism regulating high total soluble solid content in the parthenocarpic tomato fruit induced by pat-k gene

Total soluble solid (TSS) in tomatoes is an important trait that affects consumer's preference. Previous studies have observed high TSS content in parthenocarpic tomato fruits induced by a parthenocarpic gene, pat-k. However, the mechanisms regulating high TSS content remain unknown. Hence, we have investigated the water content, metabolites involved with high TSS content, and gene expression related to starch synthesis in tomato fruits to elucidate the mechanism regulating high TSS content. We have found that independent of fruit water content, parthenocarpic fruits induced by pat-k had higher TSS content than pollinated fruits on Pat-k homozygous plants. Additionally, metabolome analysis of mature fruits has revealed that fructose influenced the difference in TSS content between pollinated fruits on Pat-k homozygous plants and the parthenocarpic fruits on pat-k homozygous plants. Furthermore, high performance liquid chromatography (HPLC) analysis showed that not only fructose contents but also glucose contents were higher in the parthenocarpic fruits on pat-k homozygous plants than pollinated fruits on Pat-k homozygous plants, suggesting that increases in these sugar contents influenced the high TSS content in the pat-k-induced parthenocarpic fruits. We also have found that parthenocarpic fruits had high starch content and upregulated Sus4, which is involved in starch synthesis, during the early stages of fruit development. Since previous reports have suggested that high starch content during the early stages of fruit development attributed to high sugar content in mature tomato fruits, our results suggest that high accumulation of starch in young fruits could be involved with high TSS content in parthenocarpic fruits induced by pat-k.

Preparation and characterization of formaldehyde-free wood adhesive from mangrove bark tannin

This study sheds light on the applicability of tannin as formaldehyde-free wood adhesives. In order to replace toxic formaldehyde that exists in most commercially available wood adhesives, condensed tannins extracted from Mangrove bark (Rhizophora apiculata) via acetone and methanol extracts were modified into tannin-acetone-phenol-glyoxal (TAPG) and tannin-methanol-phenol-glyoxal (TMPG) adhesives. The extracted tannins were characterized using different complementary techniques such as Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR), thermal analysis techniques such as; thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), total phenolic content (TPC), total flavonoid content (TFC) and total condensed tannin (TCT). As for TAPG and TMPG wood adhesives, physico-chemical and mechanical properties were determined. It was found that tannin-acetone-extract (TAE) had higher TPC content compared to tannin-methanol-extract (TME). Various substitutions of adhesives were applied on plywood and mechanically tested. The 50 wt % TAPG and TMPG adhesives showed the highest tensile strength (TS) values at 70.1 ± 4.1 MPa and 66.5 ± 5.5 MPa respectively, as well as higher total solids content, viscosity, and shorter gel time compared to the control phenol-glyoxal (PG) adhesive.

Quality changes in fresh-cut asparagus with ultrasonic-assisted washing combined with cinnamon essential oil fumigation

Fresh-cut asparagus is susceptible to spoilage and quality deterioration during storage, which seriously affects its shelf-life and commercial value. The effects of ultrasonic-assisted citric acid and nisin washing (CNUS) combined with cinnamon essential oil fumigation (CEO) on microbial growth, physiological quality, and sensory characteristics of fresh-cut asparagus during storage at 4 °C were evaluated. The results showed that CNUS treatment immediately reduced the initial microbial load, and CEO treatment inhibited microbial growth during storage. CNUS + CEO treatment efficiently reduced the microbial counts and maintained acceptable levels for 20 d. In addition, CNUS + CEO treatment reduced respiration rate and weight loss, delayed respiration peak time, and maintained high ascorbic acid, chlorophyll and total soluble solids contents. Moreover, CNUS + CEO treatment greatly retarded lignin deposition by inhibiting phenylalanine ammonia lyase and peroxidase activities. CNUS + CEO treated samples had the lowest electrolyte leakage. The CNUS + CEO treatment could maintain the sensory characteristics and the shelf-life of fresh-cut asparagus for 20 d at 4 °C. Therefore, CNUS + CEO treatment could be used as an effective combination preservation technique for fresh-cut asparagus.

Comparison of metabolic kinetics during high and low solids anaerobic digestion of fecal sludge.

High solids anaerobic digestion (HS-AD) is an attractive energy-producing technology; however, high total solids (TS) content may inhibit methanogens due to high volatile fatty acid (VFA) and total ammonia nitrogenconcentrations. The objective of this paper is to quantify rate-limiting metabolic kinetic parameters to determine the influence of TS content during anaerobic digestion of fecal sludge. Two TS content:11% and 17% microcosms were analyzed. Good performance was observed in both systems, with volatile solid(VS) removalgreater than 50%, CH4 yield between 0.44 and 0.56 m3 CH4 /g VS added and cumulative CH4 production between 1.78 and 2.03 m3 CH4 /m3 digester-day. At 11% TS VFA consumption and VS removal had a positive correlation to CH4 production while the 17% TS microcosm had a negative correlation with both. This is the first study to determine the kinetic parameters for hydrolysis, VFA consumption, and methanogenesis during digestion of fecal sludge. These kinetic parameters are necessary in the design and operation of anaerobic digestion systems treating fecal sludge.

Quality testing of new Hungarian apple cultivars in normal atmosphere storage

Apples are a broadly devoured, rich wellspring of phytochemicals with many health benefits. Thus, the quality of new apple varieties should be of a high standard to please consumers. Therefore, the objective of this study was to evaluate the postharvest quality of eight apple cultivars, which were picked at different times and stored for two months before chemical component analysis. Results of the study showed significant differences among studied cultivars. Cultivar ‘Isolda’ showed a high regular fruit shape index, rich in total soluble solids content with a favorable ratio of total soluble solids content and acidity. While ‘Damra’ had a high total soluble solids content as well as pectin content. Regarding three different picking times, there was also a variation among studied apples. It can be said that these apple cultivars are suitable for fresh consumption due to their high quality. Novelty impact statement To please consumers the quality of apples should be kept high. The finding of this study revealed that new Hungarian apple cultivars showed high quality due to the high total soluble solid content, acidity, and pectin, which makes them more suitable for consumption.

Evaluation of new Turkish apricot genetic resources from the Irano-Caucasian eco-geographical group

This study presents 19 characters of 86 apricot cultivars and genotypes of the Irano- Caucasian eco-geographical group evaluated using principal component analysis. The high variability and differences among the apricot genotypes in terms of morphological, phenological and fruit quality traits were defined. The fruit size of the genotypes was generally very small (9.3 %) or small (43.0 %), the total rate of big and very big fruit genotypes was only 16.3%. The data showed that 90.1 % of the genotypes had yellow ground fruit colour, 88.4% had sweet kernel and 65% had firmness ?5 kg/cm2. About half of the apricot genotypes have 20% or high total soluble solids content. Most of the genotypes (67.3%) were harvested in mid-season and other genotypes (23.3%) were harvested early, while 4.7% of them were harvested very late, 3.5 % of the genotypes late. Only one genotype (1.2%) was harvested very early. The fruit size was highly correlated with fruit weight, pit weight and fruit flesh/pit rate. The same correlation was also observed between the fruit ground colour and fruit flesh colour. On the other hand, the total soluble solids were moderately correlated with fruit flesh firmness and seed taste. The results of the principal component analysis show that the 55% of the total variation is represented for the first three main components (22.9, 19.8, and 12.3%, respectively). The germplasm presented a large variation in the evaluated characters and most of the genotypes were found having high total soluble solids and low titratable acidity which would be beneficial for future breeding programs held to improve the related characters.

Vane geometry for measurement of influent rheological behaviour in dry anaerobic digestion

The knowledge of the rheology of influents involved in dry anaerobic digestion is an essential factor for process optimization. Despite this fact, it is difficult to characterize the rheological behaviour of these influents with high total solid (TS) content. Indeed, standard methods of rheological measurements are poorly adapted to these influents because of the sliding effects observed during the measurements. In this study, we used a non-standard method, the Vane geometry, for its particularity to limit the sliding effects. Two types of measurements were carried out on potato influents of 18–35% TS, extracted from the digesters. The first measurement was to submit to the sample a rising shear velocity ramp from 0 to 200 s−1 at 37 °C and 55 °C. The results of these measurements show a good correlation between the rheograms and Herschel-Bulkley model and we deduced a pseudoplastic threshold behaviour. The second measurement was performed in oscillations at 10 Hz at 25 °C, 37 °C and 55 °C. The results show different evolutions of the elastic G′ and viscous G″ modulus as a function of temperature. There is a crossing of G′ and G″ at 25 °C, G′ greater than G″ at 37 °C, and finally G′ and G″ forming a plateau at 55 °C, characteristic of a gel. The knowledge of these rheological behaviour is crucial for the design and operating instructions of anaerobic digestion reactors for influents with high TS content. The Vane geometry would, therefore, be an effective tool for characterizing the rheological behaviour of influents in dry anaerobic digestion.

Assessing inter and intra-variation in the characteristics of faecal sludge from Vadgaon Maval, Maharashtra: For better faecal sludge management in India

Faecal Sludge (FS) produced in developing countries has become a significant source of water pollution. The optimal treatment of FS can lead to a sustainable economy. In India, the second phase of the open defecation free (ODF) initiative (energy recovery by providing city- or town-level centralised FS treatment plants) has begun from 2019 to sustain millions of toilets. However, to achieve this goal, India must address significant knowledge gaps such as the type of available on-site sanitation treatments (OSTs), optimal time of emptying the OSTs, and variations in the FS characteristics with age. Thus, the present study analysed FS samples collected from Vadgaon Maval, Maharashtra, India, to understand the inter- and intra-variation in FS characteristics. The pH, electrical conductivity, total solids (TS), specific gravity (SG), organic matter (OM), chemical oxygen demand (COD), and pathogen content of FS samples were observed to be in the range of 7–7.65, 1.19–4.01 mS/cm, 1–123 g/L, 0.88–1.26, 18.4%–100%, 960–6080 mg/L, and 105–109 number/L of FS, respectively. The inter-variation of FS characteristics exhibited that the pH, EC, TS, and SG increased, whereas OM, settling, and drying capacity decreased with an increase in age. Fresh FS (excreta degraded for ≤3 years) was yellowish-brown in colour and exhibited low TS, low SG, and high OM. On the other hand, older FS (excreta degraded for >3 years) was blackish-brown in colour and exhibited high TS, SG, and pathogen content. This observation indicates that FS vacuum pumping may be difficult in the sludge zone after 3 years of excreta degradation, which may encourage the manual scavenging practice. Additionally, the analysis of FS treatment plant (FSTP) process control parameters (settled sludge volume, sludge volume index, and sludge drying capacity) indicated that the treatment time required for older FS is long, which increases the FSTP cost. Furthermore, FS intra-variation in OST exhibited that effluent FS could be directly sent for effluent treatment without any solid–liquid separation process. Thus, the present study can help practitioners in establishing or modifying FS treatment systems for addressing conditions based on the variation in FS characteristics at the town level in India.

Effects of alkaline electrolyzed water pretreatment on the physicochemical quality attributes of fresh nectarine during storage

Chlorinated water treatment has been extensively used to manage postharvest decontamination of fruits for decades. It has been well established that chlorine may produce undesirable by-products that have a potential carcinogenic impact on human health and toxic waste on the environment. Electrolyzed water is an eco-friendly technique that has been regarded as an effective method for decontaminating microbes on fruit surfaces. However, the impact of alkaline electrolyzed water (AEW) on the physical and biochemical quality attributes of nectarine fruit during postharvest storage is not fully understood. Therefore, this study investigated the effects of AEW treatment (200 mg/L, pH, 6.7), sodium hypochlorite, and nontreated (control) on the storability, quality attribute, and decay incidence of fresh nectarine stored at −0.5℃ and 95% RH for 31 days. Results obtained indicated that the AEW treatment effectively maintains firmness, reduced weight loss, and maintains high total soluble solid content with a slight decline in titratable acidity for nectarines. Furthermore, the AEW suppresses the decrease of color qualities of the peel L*, a*, b*, reduced the incidence of browning (h°) and surface decay compared with chlorine-treated and control fruit. Novelty impact statement Alkaline electrolyzed water (AEW) and its efficacy to minimize decay and maintain physicochemical quality of nectarine fruit compared with chlorinated water treatment were investigated. Treatment with AEW (200 mg/L, 10 min) effectively preserves the freshness of the nectarine fruit by reducing surface decay compared with the chlorine-treated and control fruit. The outcome of this study provides guiding tools for stone fruit pack-houses and other industry role players on the potential of EW as an alternative to chlorine treatments.

Impact of Yeast Supplement to the Rations Contained Different Levels of Barley Grain in Milk Production and Components of Awassi Ewes

Background: Sheep milk production after weaning is produced for a limited period of 80-100 days, it is used for cheeses manufacturing, especially in the Mediterranean region due to its high content of total solids and it preferred in human nutrition because it is rich in unsaturated fatty acids, protein, nucleotides and nucleosides, this earns therapeutic functions especially cancer prevention. On the other hand, reducing the cost of feeding is important in reducing production costs. Methods: Eighteen Awassi ewes in late lactation were used in this experiment, aged 3-5 years, average body weight 55.27 kg. Ewes were divided randomly into three groups and fed periodically on experimental rations in cross over design (3×3) each period lasted 17 days, first ration was control, second ration was similar to control and fed with addition 10 g/ ewe of Saccharomyces Cerevisiae, while in the third ration barley grain decreased to 35% and fed with added yeast. Ewes were milked on two consecutive days at the end of each experimental period and components were analysis using a milk scan analyzer. Result: Results were indicated that rations had no significant effect in milk yield and components. Also serum blood parameters of glucose, urea, cholesterol and total protein were not affected significantly.

Identification of yeasts in different rubber leaf (Hevea brasiliensis) clones and their effects on the physical properties of fermented glutinous rice tapai

Tapai is one of the most popular traditional desserts in Malaysia and other Asian countries. Traditionally, tapai is wrapped in a rubber leaf to enhance the smell and increase its palatability. The study focused on identifying the yeasts present before and after the production of glutinous rice tapai wrapped in different rubber leaves clones, namely RRIM 2025, RRIM 2002, PB 260 and PB 350. The identification of the yeast was carried out using API 20C AUX test strips for all rubber leaves clones, glutinous rice tapai wrapped in RRIM 2025, RRIM 2002, PB 260, PB 350 and in a container (control). The results showed that Crytococcus laurentii, Rhodotorula mucilaginosa 2, Candida famata, Rhodotorula minuta were present in rubber leaf clones. While the yeasts that had been identified in tapai wrapped in rubber leaf were Candida guilliermondii, Rhodotorula mucilaginosa 2, Candida parapsilosis and Trichosporon mucoides and only C. guilliermondii was found in the container. The physical properties of the tapai that are wrapped in rubber leaves have a difference in texture, pH value and total soluble solids content compared to the control sample. The tapai sample wrapped in RRIM 2025 and RRIM 2002 had a high total soluble solid content of 45.8±0.14% and 45.78±0.16% °Bx, respectively. Meanwhile, the control sample has the highest pH value and the hardest rice kernels, which were 4.71±0.05 and 218.19±25.39 N, respectively. The results showed that the different yeasts present in the rubber leaf may cause changes in the physical properties of glutinous rice tapai.

Predicting the sweetness level of avomango (Gadung Klonal 21) using multi-predictor local polynomial regression

One of the mango’s maturity aspects is the sweetness of the fruits. Mature Avomango has a high degree of sweetness, characterized by a high total soluble solids (TSS) content. Currently, many non-destructive tests are using Near Infra-Red (NIR) spectroscopy to find out the TSS content. NIR spectroscopy generates spectra data, which can be used as predictors to predict Avomangos sweetness level. This study aims to predict the level of Avomangos sweetness by using a multi-predictor local polynomial regression approach and compare it with multiple polynomial regression. In this study, we use 120 samples of Avomango divided into two parts, 100 as training data and 20 as testing data. The multi-predictor local polynomial regression has better performance with the value mean absolute percentage error (MAPE) is 8.554% that categorized as a highly accurate prediction for predicting Avomangos sweetness level.

Microstructural and rheological behavior of buffalo milk chocolates.

The development of products with buffalo milk has increased due to its peculiar characteristics, such as taste and high content of total solids, which has attracted consumers and the food industry.In this context, the objective was to develop and evaluate the microstructural properties of chocolates with different concentrations of buffalo milk powder (0%, 5%, 10%, 15% and 20%) through polymorphism, microscopy and rheological studies. For the polymorphism, the X-ray diffraction technique (XRD) was performed, while the crystal morphology was observed by scanning electron microscopy (SEM). The addition of levels of more than 10% buffalo milk caused notable changes in XRD diffractograms, demonstrating the appearance of different polymorphic forms. Microscopy analysis revealed changes in the structure of the matrix with an increase in the concentration of buffalo milk, presenting more continuous surfaces, associated with milk proteins, which have emulsifying capacity. The Herschel-Bulkley model adequately described the flow behavior of the formulations. There was an increase in all rheological properties (yield stress, viscosity, thixotropy and loss tangent (tang δ)) in chocolates with higher concentrations of milk. For that, the composition of the milk influences the degree of structuring of the chocolate. Considering this technological information, it is important to highlight that the production of buffalo milk chocolates shows potential for technological innovation.

Condensed tannin resins extracted from Pinus radiata bark as a support matrix in carbon nanofiber-reinforced polymers

Condensed tannins extracted from the Pinus radiata bark (PRTs) were used as a replacement for phenol in the synthesis of resol-type phenolic resins (FRs) and tested as polymer matrix in carbon nanofiber (CNF)-reinforced composite materials. The PRTs used herein contained a phenol and lignin content of 31 (Eq/L) and 35 (%w/w), respectively. The molecular weights of these polyphenols indicated the presence of 16 flavonoid units. Tannin resins were synthesized, and their characteristics were compared with those of the synthesized FRs using a formaldehyde/phenol ratio of (1.6/1.0), which has the highest total solids content. The results showed that the gel time and useful life of the resins decreased with the addition of the tannins, while there was no significant variation in the degradation temperature with varying FR contents. The mechanical properties of the CNF-reinforced composite materials were determined by DMA, and the results showed an increase of 1000 MPa, due to the better distribution of the fibers in the matrix. The modulus (E') in the reinforced composite materials with tannin resins was 2322 MPa and 1803 MPa without tannins, while modulus E¨ for composite materials doubled for resins with tannins. Tannins improved the dispersion of CNTs and the matrix-filled interface.

Methane gas production from a mixture of cow manure, chicken manure, cabbage waste, and liquid tofu waste using the anaerobic digestion method

Biomass is valuable alternative energy worldwide as a substitute for fossil fuels can be converted into various forms of usable energy such as heat, steam, electricity, biogas, and liquid transportation biofuels. Cabbage waste, tofu liquid waste, cow dung and chicken manure is dangerous for the surrounding environment, which produces CH4 gas and has quite high BOD and COD values. This liquid waste has an amount of COD, suspended solids, and a high total solids content. One solution to overcome this pollution is by processing the waste into biogas, especially methane gas. The material will be transformed into methane gas by fermentation through the anaerobic digestion method. Before converting into biogas, initial characterization will be carried out in total C content, total N, COD, and C/N ratio. Then, from the biogas produced, the maximum data obtained is in variable B4 (55% cow dung: 15% chicken manure: 15% cabbage waste: 15% liquid tofu waste) with a total amount of gas of 7140 ml. This shows that tofu liquid waste can increase the potential amount of biogas produced.

Quality Evaluation of Strawberries Grown in Various Regions by Singaporeans and Japanese

ABSTRACT The objective of this study was to evaluate the quality of strawberries distributed in global markets. We obtained strawberries from Egypt, Mexico, the Republic of Korea, Spain, and the United States of America (US) being sold in Singapore, and compared them with Japanese strawberries (cv. Benihoppe) using instrumental analysis and sensory evaluation. Sensory evaluation was conducted by Singaporean and Japanese assessors. The results showed that the quality of strawberries in Mexico, Spain, and Egypt were relatively close, but the others were significantly different. The strawberries from the US and Japan had high total soluble solids (TSS) content, while those from Egypt, Mexico, Spain, and the US were firmer and had higher titratable acidity (TA). In the sensory evaluation, the assessors preferred strawberries with high total soluble solids (TSS) and low titratable acidity (TA). These findings suggest that varieties with high TSS and low TA are desirable for the global market. In addition, compared with the Japanese assessors, the Singaporean assessors tended to prefer strawberries with lower TA. These preferences may change depending on the eating habits of the region.