3. Results and discussion 3.1. Chemical composition of WGP Fat, protein, soluble sugar, pectin and condensed tannin content of WGP were 11.09%, 10.32%, 3.89%, 3.68% and 12.11%, respectively (Table 1), comparable to the data in previous study (Llobera &
Table 1 Chemical composition, total phenolic content and DPPH radical scavenging activity of wine grape pomace (WGP). % composition (DM)a
a DM, dry matter. The table was modified from Tseng and Zhao (2012).
Cañellas, 2007). TPC of WGP was 67.74 mg GAE/g. Note that phenolic compounds in WGP are influenced by many factors, including grape variety, growth climate and location, harvest time, as well as processing and storage conditions, extraction and analytical methods (Lafka, Sinanoglou, & Lazos, 2007). Thimothe, Bonsi, Padilla-Zakour, and Koo (2007) reported that Pinot Noir pomace after fermentation in winemaking has slightly higher TPC than that of whole Pinot Noir fruit. In general, phenolic acids including gallic acid and ellagic acid, and flavonoids, such as catechin, epicatechin, procyanidins and anthocyanins are the major polyphenols in WGP (Lafka et al., 2007; Yilmaz & Toledo, 2006). Lu and Foo (1999) detected 17 polyphenols in WGP by NMR spectroscopy; Schieber, Kammerer, Claus, and Carle (2004) further quantified 13 anthocyanins, 11 phenolic acids, 13 flavonoids, and two stilbenes in WGP by HPLC. Anthocyanin that contributed to the colour of the WGP was identified as malvidin derivatives, malvidin-3-glucoside and malvidin-3-acetylglucoside (de Torres, Díaz-Maroto, HermosínGutiérrez, & Pérez-Coello, 2010). Phenolic compounds are the secondary metabolites of plants and characterized by the structure–activity relationship of the hydroxyl group and the nature of substitutions on aromatic ring. Based on their structure–activity relationship, there are several different antioxidant mechanisms of phenolics, such as free radicals scavenging ability, hydrogen atoms or electron donation and metal cations chelation (Amarowicz, Pegg, Rahimi-Moghaddam, Barl, & Weil, 2004). Total DF content of WGP was about 61%, met the definition of ADF with over 50% dry matter. In respect to RSA, 1 mg AAE/g equalled to 2.45 mg a-tocopherol equilibrium (TE)/g based on our previous study (Tseng & Zhao, 2012). RSA of WGP was 37.46 AAE/g or 91.78 TE/g, also met the requirement for ADF of having free radical scavenging at least equivalent to 50 mg of vitamin E by DPPH method. These properties are intrinsic to the WGP, deriving from the natural constituents of the material. Additionally, WGP retained the ADF characteristic even after 16 weeks of storage at 15 C in vacuum package (Tseng & Zhao, 2012). Therefore, WGP could be claimed as antioxidant dietary fibre and fortified in yogurt and salad dressings in this study (Table 2).
3.2. Colour of WGP and WGP fortified yogurt and salad dressings L⁄ , Hue and Chroma values of freeze dried WGP and its fortified products are presented in Table 3. The control yogurt sample without the addition of WGP received the highest L⁄ of 92.18, but the lowest Hue value of 1.26. As expected, the lightness and Hue values decreased, but the Chroma increased along with increased amount of WP added, but no significant difference (P < 0.05) between 2% WP and 3% WP (w/w yogurt) samples. Overall, LE-Y and FDF-Y samples obtained the higher (P < 0.05) L⁄ and Hue values, but lower Chroma value than those of 2% WP (w/w yogurt)
Table 2 Dietary fibre fractions of wine grape pomace (WGP) and WGP fortified yogurt and salad dressings.
Means followed by the same lowercase letters (a–d) in the same column within each concentration were not significantly different (P > 0.05). Control, no pomace added; WP, whole pomace powder; LE, pomace liquid extract; FDE, freeze dried pomace extract.
b The commercial FiberOne yogurt contained 5% dietary fibre from blueberries (YoPlait, USA).
a Means followed by the same lowercase letters (a–d) in the same column within each concentration were not significantly different (P > 0.05). Control, no pomace added; WP, whole pomace powder; LE, pomace liquid extract; FDE, freeze dried pomace extract. b The commercial FiberOne yogurt contained 5% dietary fibre from blueberries (YoPlait, USA).
Table 3 Colour of wine grape pomace (WGP) and WGP fortified yogurt and salad dressing.a
Means followed by the lowercase letters (a–d) in the same column within each concentration of WGP fortified product were not significantly different (P > 0.05). Control, no pomace added; WP, whole pomace powder; LE, liquid pomace extract; FDE, freeze dried pomace extract.
sample. These results reflected that the LE and FDE fortified samples provide more homogeneous but less saturated colour in the product. Also, WP presented more redness and blueness compared to LE and FDE that showed higher a⁄ value, but lower b⁄ value (data not shown). In respect to WGP fortified salad dressings, the control sample received the lightest colour, 43.59 and 72.25 in Italian and Thousand Island dressing, respectively, while the darkest colour was found in 1% WP (w/w Italian) (36.96) and 2% WP (w/w Thousand Island) (60.33) samples. In Italian dressing, the lowest Hue value was found in LE-I (1.09), but no difference (P > 0.05) among all Thousand Island samples regardless of the concentration and type of WGP added. Both Italian and Thousand Island samples had the high Chroma value of 29.06 and 39.47, respectively, and the samples with the highest amount of WGP received the lowest Chromavalues, 21.79 in 1% WP (w/w Italian) and 28.16 in 2% WP (w/w Thousand Island).
3.3. pH of WGP fortified yogurt and salad dressings Fig. 1 shows the pH of WGP fortified products during 4 weeks of storage under 4 C. Adding WGP into the yogurt immediately reduced the pH from 4.78 to 4.47–4.60. Since WGP liquid extract had a low pH of 3.63, LE-Y showed the lowest pH of 4.47. The pH of all samples continuously dropped (P < 0.05) during the first 2 weeks of storage. At the end of 4 weeks, control sample had the highest pH of 4.44, while LE-Y had pH of 4.30. These results were consistent with previous study in orange fibre fortified yogurt, in which about 0.2 unit of pH reduction was observed after 14 days of storage (García-Pérez et al., 2005). Beal, Skokanova, Latrille, Martin, and Corrieu (1999) explained that the high rate of production of lactic acid and galactose was observed at the initial 14 days due to the high bacterial metabolic activity with the consumption of lactose. The pH of WGP fortified Italian salad dressing was lower than control initially, but no difference (P > 0.05) in pH among all forti- fied samples no matter of the type and concentration of WGP added. The control and WGP fortified samples had pH of 3.41 and 3.38, respectively at day 0. Overall, the pH was slightly dropped during storage under 4 C and received the value of 3.35 and 3.31 in control and 1% WP (w/w Italian) samples, respectively
Fig. 1. pH value of samples during storage at 4 C. (A) WGP fortified yogurt, (B) WGP fortified Italian salad dressing, and (C) WGP fortified Thousand Island salad dressing.
at the end of 4 weeks of storage. For Thousand Island salad dressing, 2% WP (w/w Thousand Island) obtained the relatively low pH of 3.53, whereas the control had a pH of 3.57. The pH of LE-T sample was slightly higher, probably due to the higher pH of the extract. The pH of the Thousand Island dressing remained stable, about 3.5–3.6 during 4 weeks of storage.
3.4. Syneresis, viscosity and lactic acid percentage of WGP fortified yogurt Based on our preliminary study, 2% reduced fat milk could not coagulate if >5% WP (w/w yogurt) was added before fermentation. Also, it required longer fermentation time when adding more than 3% WP (w/w yogurt) into milk beforehand, which was undesirable due to increasing in syneresis. Mazaheri Tehrani and Shahidi (2008) also found that syneresis was lower when fruit were added after fermentation. Therefore, WGP was added after the milk had coagulated, i.e., yogurt had formed in this study. Viscosity, syneresis and lactic acid percentage of WGP fortified yogurt during 4 weeks of storage at 4 C are reported in Table 4. No difference (P > 0.05) on syneresis among all the samples was observed initially, ranged from 16.82% to 20.13% (Table 4). The syneresis increased significantly (P < 0.05) only in 3% WP (w/w yogurt) sample (33.58%), while all other samples remained stable during 3 weeks of storage. The amount of WP addition in yogurt is critical because the protein in WP rearranged the gel matrix. Hence, 2% WP (w/w yogurt) was selected as the optimum level of WGP fortification in yogurt and the same concentration was then applied to select the level of LE-Y and FDE-Y to be added in yogurt. Staffolo et al. (2004) reported that no syneresis was occurred when yogurt was fortified with 1.3% of wheat, bamboo, inulin and apple fibre during 21 days of storage. Adding WGP reduced viscosity of yogurt, in which 3% WP (w/w yogurt) sample had the lowest value of 533 cP, while it was 1267 cP in the control (Table 4). This result was probably because stirring high concentration of WP in yogurt broke down the coagulated milk, thus reducing the viscosity. Viscosity of FDE-Y and WP fortified yogurt samples all increased during 3 weeks of storage, in which FDE-Y samples increased from 1533 to 3407 cP, and 1% WP, 2% WP and 3% WP (w/w yogurt) samples increased 252%, 351% and 428%, respectively, higher than those of control, LE-Y and FDE-Y samples, probably contributed by the insoluble dietary fibre fraction in WP. Ramaswamy and Basak (1992) stated that the addition of WGP or fruit concentrate generally decreased the consistency of the products owning to reduced water-binding capacity of proteins. During the storage time, the increased viscosity could be regarded as recovery of structure or rebodying (Lee & Lucey, 2010). In addition, dietary fibre in WGP may influence the viscosity of the pro
Results (
Thai) 1:
[Copy]Copied!
3. ผล 3.1 การสนทนา องค์ประกอบทางเคมีของ WGP ไขมัน โปรตีน น้ำตาลละลาย เพกทิน และแทนนินบีบเนื้อหาของ WGP คำ 11.09%, 10.32%, 3.89%, 3.68% 12.11% ตามลำดับ (ตารางที่ 1), เทียบเท่ากับข้อมูลในการศึกษาก่อนหน้า (Llobera &ตารางที่ 1 องค์ประกอบทางเคมี ฟีนอเนื้อหารวม และ DPPH scavenging กิจกรรมรุนแรงของไวน์องุ่น pomace (WGP) องค์ประกอบ% (DM) การเป็น DM เรื่องแห้ง ตารางถูกปรับเปลี่ยนจากหยานีและเจียว (2012)Cañellas, 2007). TPC of WGP was 67.74 mg GAE/g. Note that phenolic compounds in WGP are influenced by many factors, including grape variety, growth climate and location, harvest time, as well as processing and storage conditions, extraction and analytical methods (Lafka, Sinanoglou, & Lazos, 2007). Thimothe, Bonsi, Padilla-Zakour, and Koo (2007) reported that Pinot Noir pomace after fermentation in winemaking has slightly higher TPC than that of whole Pinot Noir fruit. In general, phenolic acids including gallic acid and ellagic acid, and flavonoids, such as catechin, epicatechin, procyanidins and anthocyanins are the major polyphenols in WGP (Lafka et al., 2007; Yilmaz & Toledo, 2006). Lu and Foo (1999) detected 17 polyphenols in WGP by NMR spectroscopy; Schieber, Kammerer, Claus, and Carle (2004) further quantified 13 anthocyanins, 11 phenolic acids, 13 flavonoids, and two stilbenes in WGP by HPLC. Anthocyanin that contributed to the colour of the WGP was identified as malvidin derivatives, malvidin-3-glucoside and malvidin-3-acetylglucoside (de Torres, Díaz-Maroto, HermosínGutiérrez, & Pérez-Coello, 2010). Phenolic compounds are the secondary metabolites of plants and characterized by the structure–activity relationship of the hydroxyl group and the nature of substitutions on aromatic ring. Based on their structure–activity relationship, there are several different antioxidant mechanisms of phenolics, such as free radicals scavenging ability, hydrogen atoms or electron donation and metal cations chelation (Amarowicz, Pegg, Rahimi-Moghaddam, Barl, & Weil, 2004). Total DF content of WGP was about 61%, met the definition of ADF with over 50% dry matter. In respect to RSA, 1 mg AAE/g equalled to 2.45 mg a-tocopherol equilibrium (TE)/g based on our previous study (Tseng & Zhao, 2012). RSA of WGP was 37.46 AAE/g or 91.78 TE/g, also met the requirement for ADF of having free radical scavenging at least equivalent to 50 mg of vitamin E by DPPH method. These properties are intrinsic to the WGP, deriving from the natural constituents of the material. Additionally, WGP retained the ADF characteristic even after 16 weeks of storage at 15 C in vacuum package (Tseng & Zhao, 2012). Therefore, WGP could be claimed as antioxidant dietary fibre and fortified in yogurt and salad dressings in this study (Table 2).3.2. สีของ WGP และ WGP ธาตุโยเกิร์ตและสลัดแผล L⁄ เว้ และตรึงค่าความแห้ง WGP และผลิตภัณฑ์ของธาตุจะแสดงในตาราง 3 ตัวอย่างโยเกิร์ตควบคุม โดยไม่มีการเพิ่มของ WGP รับ L⁄ สูงสุดของ 92.18 แต่เว้ค่าต่ำสุดของ 1.26 ตามที่คาดไว้ ลดความสว่างและค่าเว้ แต่ความเพิ่มขึ้นพร้อมกับเพิ่มจำนวน WP เพิ่ม แต่ไม่แตกต่างอย่างมีนัยสำคัญ (P < 0.05) ระหว่าง WP 2% และ 3% WP (w/w โยเกิร์ต) ตัวอย่างการ โดยรวม ตัวอย่างเลอ Y และ FDF Y ได้สูง (P < 0.05) ค่า L⁄ และเว้ แต่ต่ำกว่าค่าความกว่าของ WP 2% (w/w โยเกิร์ต)ตารางที่ 2 เศษส่วนใยอาหารไวน์องุ่น pomace (WGP) และแผลสลัดโยเกิร์ตธาตุ WGPไม่ได้หมายความตามตัวอักษรพิมพ์เล็กเดียวกัน (a – d) ในคอลัมน์เดียวกันในแต่ละความเข้มข้นแตกต่างกันอย่างมีนัยสำคัญ (P > 0.05) ควบคุม pomace ไม่เพิ่ม WP, pomace ทั้งผง เลอ สารสกัดเหลว pomace FDE สารสกัด pomace แห้งแช่แข็ง บีโยเกิร์ต FiberOne พาณิชย์อยู่ 5% ใยอาหารจากบลูเบอร์รี่ (YoPlait สหรัฐอเมริกา)ไม่ถูกวิธีแล้วตาม ด้วยตัวพิมพ์เล็กเหมือนกัน (a – d) ในคอลัมน์เดียวกันในแต่ละความเข้มข้นแตกต่างกันอย่างมีนัยสำคัญ (P > 0.05) ควบคุม pomace ไม่เพิ่ม WP, pomace ทั้งผง เลอ สารสกัดเหลว pomace FDE สารสกัด pomace แห้งแช่แข็ง บีโยเกิร์ต FiberOne พาณิชย์อยู่ 5% ใยอาหารจากบลูเบอร์รี่ (YoPlait สหรัฐอเมริกา)ตาราง 3 สีไวน์องุ่น pomace (WGP) และ WGP ธาตุโยเกิร์ตสลัด dressing.a หมายถึงตาม ด้วยอักษรตัวพิมพ์เล็ก (a – d) ในคอลัมน์เดียวกันในแต่ละความเข้มข้นของผลิตภัณฑ์ธาตุ WGP ไม่แตกต่างกันอย่างมีนัยสำคัญ (P > 0.05) ควบคุม pomace ไม่เพิ่ม WP, pomace ทั้งผง เลอ pomace เหลวแยก FDE สารสกัด pomace แห้งแช่แข็งตัวอย่างการ ผลลัพธ์เหล่านี้สะท้อนว่า เลอและ FDE ธาตุตัวอย่างให้เป็นเนื้อเดียวกันแต่สีไม่อิ่มตัวในผลิตภัณฑ์ ยัง WP แสดงแดงมากขึ้นและเมื่อเทียบกับเลอและ FDE ที่พบสูงค่า a⁄, blueness แต่ค่า b⁄ ต่ำ (ข้อมูลไม่แสดง) ในความเคารพ WGP ธาตุสลัดแผล ตัวอย่างควบคุมรับสีน้ำหนักเบาที่สุด 43.59 และ 72.25 ในอิตาลีและพันเกาะแต่งตัว ตามลำดับ ในขณะที่สีมืดมากที่สุดพบใน WP 1% (w/w อิตาลี) (36.96) WP 2% (w/w พันเกาะ) และตัวอย่าง (60.33) ในอิตาลีแต่ง เว้ค่าต่ำสุดพบในเลอ-ฉัน (1.09), แต่ไม่แตกต่าง (P > 0.05) ระหว่างตัวอย่างเกาะพันทั้งหมดโดยความเข้มข้นและชนิดของ WGP ที่เพิ่มขึ้น ตัวอย่างอิตาลีและเกาะพันมีค่าความสูงของ 29.06 และ 39.47 ตามลำดับ และตัวอย่างที่ มียอดสูงสุดของ WGP รับ Chromavalues ต่ำ 21.79 ใน 1% WP (w/w อิตาลี) และ 28.16 ใน 2% WP (w/w พันเกาะ) 3.3. pH of WGP fortified yogurt and salad dressings Fig. 1 shows the pH of WGP fortified products during 4 weeks of storage under 4 C. Adding WGP into the yogurt immediately reduced the pH from 4.78 to 4.47–4.60. Since WGP liquid extract had a low pH of 3.63, LE-Y showed the lowest pH of 4.47. The pH of all samples continuously dropped (P < 0.05) during the first 2 weeks of storage. At the end of 4 weeks, control sample had the highest pH of 4.44, while LE-Y had pH of 4.30. These results were consistent with previous study in orange fibre fortified yogurt, in which about 0.2 unit of pH reduction was observed after 14 days of storage (García-Pérez et al., 2005). Beal, Skokanova, Latrille, Martin, and Corrieu (1999) explained that the high rate of production of lactic acid and galactose was observed at the initial 14 days due to the high bacterial metabolic activity with the consumption of lactose. The pH of WGP fortified Italian salad dressing was lower than control initially, but no difference (P > 0.05) in pH among all forti- fied samples no matter of the type and concentration of WGP added. The control and WGP fortified samples had pH of 3.41 and 3.38, respectively at day 0. Overall, the pH was slightly dropped during storage under 4 C and received the value of 3.35 and 3.31 in control and 1% WP (w/w Italian) samples, respectivelyFig. 1. pH value of samples during storage at 4 C. (A) WGP fortified yogurt, (B) WGP fortified Italian salad dressing, and (C) WGP fortified Thousand Island salad dressing.at the end of 4 weeks of storage. For Thousand Island salad dressing, 2% WP (w/w Thousand Island) obtained the relatively low pH of 3.53, whereas the control had a pH of 3.57. The pH of LE-T sample was slightly higher, probably due to the higher pH of the extract. The pH of the Thousand Island dressing remained stable, about 3.5–3.6 during 4 weeks of storage. 3.4. Syneresis, viscosity and lactic acid percentage of WGP fortified yogurt Based on our preliminary study, 2% reduced fat milk could not coagulate if >5% WP (w/w yogurt) was added before fermentation. Also, it required longer fermentation time when adding more than 3% WP (w/w yogurt) into milk beforehand, which was undesirable due to increasing in syneresis. Mazaheri Tehrani and Shahidi (2008) also found that syneresis was lower when fruit were added after fermentation. Therefore, WGP was added after the milk had coagulated, i.e., yogurt had formed in this study. Viscosity, syneresis and lactic acid percentage of WGP fortified yogurt during 4 weeks of storage at 4 C are reported in Table 4. No difference (P > 0.05) on syneresis among all the samples was observed initially, ranged from 16.82% to 20.13% (Table 4). The syneresis increased significantly (P < 0.05) only in 3% WP (w/w yogurt) sample (33.58%), while all other samples remained stable during 3 weeks of storage. The amount of WP addition in yogurt is critical because the protein in WP rearranged the gel matrix. Hence, 2% WP (w/w yogurt) was selected as the optimum level of WGP fortification in yogurt and the same concentration was then applied to select the level of LE-Y and FDE-Y to be added in yogurt. Staffolo et al. (2004) reported that no syneresis was occurred when yogurt was fortified with 1.3% of wheat, bamboo, inulin and apple fibre during 21 days of storage. Adding WGP reduced viscosity of yogurt, in which 3% WP (w/w yogurt) sample had the lowest value of 533 cP, while it was 1267 cP in the control (Table 4). This result was probably because stirring high concentration of WP in yogurt broke down the coagulated milk, thus reducing the viscosity. Viscosity of FDE-Y and WP fortified yogurt samples all increased during 3 weeks of storage, in which FDE-Y samples increased from 1533 to 3407 cP, and 1% WP, 2% WP and 3% WP (w/w yogurt) samples increased 252%, 351% and 428%, respectively, higher than those of control, LE-Y and FDE-Y samples, probably contributed by the insoluble dietary fibre fraction in WP. Ramaswamy and Basak (1992) stated that the addition of WGP or fruit concentrate generally decreased the consistency of the products owning to reduced water-binding capacity of proteins. During the storage time, the increased viscosity could be regarded as recovery of structure or rebodying (Lee & Lucey, 2010). In addition, dietary fibre in WGP may influence the viscosity of the pro
Being translated, please wait..
