Low Sour Research Articles

Sensory identity of wine from the ancient and almost forgotten grape variety Timorasso

Over the last few decades, there has been a gradual decrease in natural biodiversity, which is leading to the standardisation of wine products. Minor grape varieties possess key traits for producing wines with a specific territorial identity and they contribute to increasing biodiversity. Timorasso is an ancient Italian white grape variety native to the province of Alessandria in the Piedmont region. It fell into oblivion for a period of time due to the advent of phylloxera at the end of the 1800s and the abandonment of rural areas, which almost led to the extinction of this grapevine. This study aimed to identify the sensory properties that characterise Timorasso wine from different producers and production areas and to investigate the diversity of the sensory space. Sixteen Timorasso wines from the 2018 vintage and were evaluated for sensory description by a panel of nine semi-trained judges using the RATA method. The Timorasso wine was found to have a complex aromatic profile spanning fruity (citrus, tropical fruits, tree-fruit and dried/baked fruit), floral, vegetative, balsamic, honey and fuel/petroleum. The multiple factor analysis clearly differentiated wines with fruity notes from those with balsamic, vegetative and fuel/petroleum aromas. The hierarchical cluster analysis evidenced three main clusters. Cluster 1 comprised wines with pale-yellow colour and fruity-related aromas, low sourness, body and alcohol sensations. Cluster 2 comprised wines with dark yellow colour, low sourness, and high intensities of raisin and fuel aromas, probably due to specific oenological practices, such as grape maceration. Cluster 3 comprised wines with high sourness and vegetative odour. The results provide for the first time a sensory map of a grapevine that was almost forgotten until a few decades ago, but which is now considered to be among the most promising white wines on the Italian market.

Effect of Fermentation Parameters on the Anthocyanin Content, Sensory Properties, and Physicochemical Parameters of Potato Blueberry Yogurt

Fruit yogurt with a variety of nutrients and fruit flavors is becoming increasingly popular among consumers. This study was conducted to achieve the optimum fermentation process parameters in preparing potato blueberry yogurt with high nutritional value and good flavor and taste by using one factor at a time experiment and response surface methodology. The optimum fermentation process was as follows: 33% potato saccharification solution, 22% blueberry juice, 38 °C fermentation temperature, 3.7% sucrose, 14% skimmed milk powder, 4% concentration of inoculum probiotics including Bifidobacterium animalis subsp. lactis BZ11, Lactobacillus plantarum LB12, and Streptococcus thermophilus Q-1 with their inoculum ratio of 1:1:2 and 12.5 h fermentation time. Potato saccharification solution, blueberry juice, fermentation temperature, and sucrose significantly affected the sensory value and quality of yogurt. Under this fermentation process, the sensory score of yogurt was 89.78. The prepared potato blueberry yogurt was rich in anthocyanins (9.41 mg/100 g), had a potential probiotic viable count of 9.31 log CFU/mL and pleasing color, and overcame the bitterness of potatoes. Electronic tongue analysis also shows that the potato blueberry yogurt had good sensory characteristics, such as high saltiness, umami, and aftertaste-A; low sourness, bitterness, and astringency; and moderate aftertaste-B and richness. This study laid the foundation for producing potato blueberry yogurt with good sensory value and high anthocyanin content.

Comparing liking and attitudes of Chinese immigrants in New Zealand towards drinkable yoghurt: an exploratory study

Whilst food choices may change when exposed to a new culture, the time and extent of the acculturation process is not clear. Focus groups (FGs) were used to explore whether recent Chinese immigrants to New Zealand (NZ) could be representative of consumer product opinions in China and whether these could be associated with residence time. Four population groups - Chinese in Beijing (BJ), Chinese in NZ for less (CH < 3y) or more (CH > 3y) than 3 years, and NZ Europeans in NZ (NZE) - were recruited to consider drinking yoghurt. FGs were conducted in Chinese or English using the same discussion guide. Transcripts were uploaded into NVivo software to extract key themes using an interpretive coding approach. CH < 3y described a liking for sweet yoghurt with low sourness, aligning with BJ. However, CH > 3y closely matched NZE, particularly for sweetness intensity. The only attribute that was not affected across immigrants was “thickness”, where thick drinking yoghurt was liked more, in line with BJ, compared to NZE. Reasons, type and temperature of consumption described by CH < 3y closely matched BJ, but some habits had changed, particularly regarding consumption at breakfast time. In contrast, CH > 3y mainly consume chilled yoghurt closely aligning with NZE, indicating that habits were associated with residence time. This exploratory study revealed that, for English speaking Chinese immigrants, the acculturation processes could take at least 3 years to affect immigrant attribute liking, but liking for some attributes was maintained, even after a longer time of residence. This understanding suggests that, with caution, recent immigrants may be an option to mimic overseas consumers in initial consumer product evaluations, especially when travelling is not possible in pandemic situations.

Volatiles Influencing Sensory Attributes and Bayesian Modeling of the Soluble Solids-Sweetness Relationship in Strawberry.

Descriptive analysis via trained sensory panels has great power to facilitate flavor improvement in fresh fruits and vegetables. When paired with an understanding of fruit volatile organic compounds, descriptive analysis can help uncover the chemical drivers of sensory attributes. In the present study, 213 strawberry samples representing 56 cultivars and advanced selections were sampled over seven seasons and subjected to both sensory descriptive and chemical analyses. Principal component analysis and K-cluster analyses of sensory data highlighted three groups of strawberry samples, with one classified as superior with high sweetness and strawberry flavor and low sourness and green flavor. Partial least square models revealed 20 sweetness-enhancing volatile organic compounds and two sweetness-reducing volatiles, many of which overlap with previous consumer sensory studies. Volatiles modulating green, sour, astringent, overripe, woody, and strawberry flavors were also identified. The relationship between soluble solids content (SSC) and sweetness was modeled with Bayesian regression, generating probabilities for sweetness levels from varying levels of soluble solids. A hierarchical Bayesian model with month effects indicated that SSC is most correlated to sweetness toward the end of the fruiting season, making this the best period to make phenotypic selections for soluble solids. Comparing effects from genotypes, harvest months, and their interactions on sensory attributes revealed that sweetness, sourness, and firmness were largely controlled by genetics. These findings help formulate a paradigm for improvement of eating quality in which sensory analyses drive the targeting of chemicals important to consumer-desired attributes, which further drive the development of genetic tools for improvement of flavor.

Effect of High Fructose Syrup (HFS) Addition on Chemical and Organoleptic Properies of Green Coconut Water Kefir

This research aims to determine the effect of High Fructose Syrup (HFS) addition to carbon dioxide (CO2) content, ethanol content and organoleptic properties of green coconut water kefir, and to determine the ideal HFS concentration for green coconut water kefir. Complete Randomized Design is used in this research with 5 treatments and 4 replications i.e. T0 (0% v/v HFS), T1 (2.5% v/v HFS), T2 (5% v/v HFS), T3 (7.5% v/v HFS), and T4 (10% v/v HFS). The CO2 content is measured by sodium carbonate (Na2CO3) titration, ethanol content is measured by distillation, while the organoleptic properties that included level of sourness, level of sweetness, soda sensation, sour aroma, and viscosity are done by 25 panelists. The results show that the addition of HFS is statistically gave significant effect to the CO2 content and organoleptic properties (P&lt;0,05). However, the ethanol content, which analyzed using empirical model of quadratic polynomial regression, show that the addition of HFS is incompatible to the ethanol content of green coconut water kefir. The most optimal HFS concentration is 7.5% v/v, resulting CO2 content of 0.096%; ethanol content 1.545%; and desirable organoleptic properties, which are low level of sourness, high level of sweetness, very high soda sensation, low sour aroma, and high viscosity.

Identification and Fermentation Characteristics of Lactic Acid Bacteria that Produce Soy Curd With Low Sour Taste

Identification and Fermentation Characteristics of Lactic Acid Bacteria that Produce Soy Curd With Low Sour Taste

Flavour and texture changes in apple cultivars during storage

Storage induced sensory changes of Finnish apples were defined and quantified with descriptive analysis. Twelve cultivars were evaluated at 3–5 storage points during 8–17 weeks (+3 °C). The lexicon consisted of 15 attributes: two related to odour (fruity, intensity), five to texture (hard, crispy, mealy, juicy, soggy), five to flavour (sour, sweet, astringent, intensity, diversity), and three to deterioration (mouldy odour, fermented odour/flavour). Major changes were observed during the follow-up period, but differences in cultivar performance were large. Storage influenced mostly texture, especially juiciness and mealiness. Sourness diminished in several cultivars. Hierarchical cluster analysis on attribute intensities revealed four distinctive clusters (CL). Apples in CL1 were juicy, crispy and sour with high flavour intensity. In CL2 and CL3 apples were medium sour, but in the latter crispier, juicier and sweeter. Apples in CL4 were sweet and medium mealy with low sourness. During storage, most cultivars shifted clusters, especially to CL2 and CL4, indicating that storage time modifies their sensory profiles. Thus, not only the cultivar, but also the storage time shapes the sensory properties. Understanding that cultivars may belong to different clusters in the course of storage, and consequently appeal to different consumer segments, should be helpful for marketing.

Volatile composition and sensory quality of Spanish pomegranates (Punica granatumL.)

Pomegranate is highly valued for its health-promoting effects. Fruits of nine pomegranate cultivars were analysed for volatile compounds, antioxidant activity and quality parameters, including maturity index and CIEL*a*b* colour. Volatile compounds were isolated from fresh juices using hydrodistillation; extracts were analysed using gas chromatography/mass spectrometry. Fruit colour was influenced by cultivar and grouping of cultivars according to their taste (sweet, sour-sweet or sour), with sweet fruits having more intense red colour and higher lightness values. A total of 18 compounds were found in pomegranate aroma profiles, including monoterpenes, aldehydes, alcohols, monoterpenoids and linear hydrocarbons. The most abundant compound were trans-2-hexenal, 3-carene, α-terpinene and α-terpineol. The total concentration of volatiles ranged from 1.7 to 10.9 g kg(-1) . Overall consumer liking of pomegranate juices was associated with the presence of monoterpenes such as α-pinene, β-pinene, β-myrcene, limonene and γ-terpinene. The presence of aldehydes such as hexanol, hexanal and cis-3-hexenol was correlated with poor overall consumer liking. Fruits from the cultivar Mollar de Elche 2 were those most suited for juice processing because they had the highest total concentration of volatiles, which was related to high overall consumer liking, intense and acceptable fresh pomegranate odour and flavour (high scores of satisfaction degree), medium intensity of red colour and low sourness.

The kinetics of crossflow dynamic membrane bioreactor

Crossflow dynamic membrane bioreactor (CDMBR) kinetics was investigated by treating caprolactam wastewater over a period of 180 d. The removal efficiencies of organic substances and nitrogen averaged over 99% and 80%, respectively. The observed sludge yield was only 0.14 g SS·g-1 COD·d-1 at an SRT of 30 d and sludge organic loading about 0.3 g COD·g-1 SS·d-1. Based on total organic carbon TOC measurement, accumulation of soluble microbial products (SMP) in the supernatant caused by membrane separation was observed during the initial operational period. SMP in the supernatant was verified biodegradable subsequently through molecular weight distribution (MWD) analysis. Specific oxygen uptake rate (sOUR) decreased with MLSS increasing in the reactor, which could be expressed by a exponential function. sOUR maintained in the range of 4-5 mg O2·h-1·g -1 VSS while oxygen uptake rate (OUR) increased with MLSS concentration. Despite the low sOUR level of Nitrosomo and Nitrobacter, nitrifying capacity of CDMBR remained high enough to qualify nitrogen removal. Water SA Vol.32 (2) 2006: pp.199-204

Comparison of Submerged Membrane Bioreactor in Different SRT Conditions

Complete sludge retention MBR appears to be an innovative technology which no sludge will be produced, hence eliminating the sludge disposal cost. However, the understanding of microbial behaviour in the complete sludge retention MBR was still not adequately established. This study was conducted to investigate the biological performances and microbial behaviour of three different SRT MBRs (5 days SRT, 10 days SRT and prolonged SRT). The results revealed that membrane filtration assisted for maintaining the high degree of organic removal (above 97%) for all MBRs. High organic degradation was noticed in the prolonged SRT MBR (89.44%) compared with 5 days SRT (77.64%) and 10 days SRT (85.62%) MBRs. This showed that the prolonged SRT MBR posed a greater capability for further degradation of inert organics and SMP. Extremely low sludge yield (0.0388 g VSS/g COD) was occurred in the prolonged SRT condition compared with 5 and 10 days SRT conditions. The low SOUR did not affect the degradation performance. Whereas, it implied that small amount of oxygen was sufficient to achieve high degree of organic degradation during the prolonged SRT MBR condition.

Preparation and Characteristics of Calcium Lactate from Black Snail

Calcium lactate (CL) prepared from powdered black snail (PBS) or its ashed powder (ABS), was investigated for ideal manufacturing conditions to optimize color, solubility and sensory quality. Based on the amount of PBS and 100 mL lactic acid (LA), the yields of PBS-CL were 300% and 15 g in 10% LA and 260% and 20 g in 20% LA. Yields of ABS-CL based on the amount ABS and 100 mL LA were 400% and 60 g in 10% LA and 329% and 66 g in 20% LA. Both of the yields were decreased with an increase of the LA concentration on the basis of PBS and ABS amounts, but proportionally increased with the increment in the LA concentration on the basis of LA volume. Optimal preparation times of the dehydrated PBS-CL and ABS-CL were, respectively, 4 hr and 5 hr at 100℃, 3 hr and 4 hr at 120℃, and 1 hr and 2 hr at 150℃, which showed shorter time in preparing the dehydrated ABS-CL. PBS-CL and ABS-CL were confirmed to be Ca(CH₃CHOHCO₂)₂ by the analysis results of IR and ¹H-NMR. Calcium contents of the anhydrous PBS-CL and ABS-CL were individually 15.4% (w/w) and 17.3% (w/w) representing 84.2% and 94.5% of each theoretical value. Colors of PBS-CL and ABS-CL were light yellow and light-greenish white each. Solubilities of PBS- CL and ABS-CL in distilled water at pH 3～8 were 5.43 and 6.11 g/100 mL, respectively, which demonstrated higher mean solubilities rather than the 4.74 g/100 mL of standard CL. Solubilities of PBS-CL (3.14～5.03 g/100 mL) and ABS-CL (4.69～6.05 g/100 mL) against soup soy sauce, 3% brine, Soju (Korean distilled liquor), thick soy sauce, grape juice and orange juice were higher than those of standard CL (2.94～5.84 g/100 mL). ABS-CL was believed to have a wide use range due to its low sourness while different applications of PBS-CL in food are expected due to its mild astringent taste and strong savory taste despite its strong bitter taste as estimated by sensory evaluation.

Sensory characteristics of cooked pork loin as affected by nucleotide content and post-mortem meat quality

Muscle longissimus dorsi excised at 2 hr post mortem was utilised to study the effect of post-mortem meat quality, and their content of nucleotide metabolites, on the sensory characteristics of cooked loin. Four different post mortem meat qualities were defined: pale soft exudative (PSE), red soft exudative (RSE), red firm non-exudative (RFN) and dark firm dry (DFD). The DFD meat quality class showed low sour and salty tastes and a high sweet taste, low astringency and high juiciness and tenderness, giving the best overall quality. On the other hand, the RSE quality class produced a meat with a low juiciness and high hardness, and a low overall quality although these differences were not significant ( p<0.05) against RFN and PSE meats. The effect of nucleotide metabolite contents on the sensory meat properties were most significant on taste although, the different meat qualities were only significantly different ( p<0.05) in the content of hypoxanthine, guanosine, GDP and IDP.

Sensory attributes and acceptance of sucrose and fat in strawberry yoghurts

SummaryYoghurts containing approximately 0.1, 1.5, 3.2, or 5.2% dairy fat were sweetened with 6, 8, 10, or 12% sucrose and flavoured with strawberry jam. the sweetness, fattiness, and sourness of the resulting 16 samples were rated by a laboratory panel (n= 14), and the hedonic responses by a consumer panel (n= 41). As expected, the sweetness and fattiness increased with increasing sucrose and fat contents, respectively. Sucrose enhanced perceived fattiness and fat enhanced sweetness. Sourness was suppressed by both. the sample with 10% sucrose and 3.5% fat received the highest, and the samples with the lowest sucrose and fat contents the lowest, pleasantness ratings. Among the consumers, men preferred high sweetness and fattiness and low sourness, but women did not show any definite tendencies. Although the consumer panel was small, the results demonstrate the importance of segmenting consumers to predict product success.