diff --git a/spring-cloud-stream-binders/spring-cloud-stream-binder-test/src/test/java/org/springframework/cloud/stream/binder/MessageChannelBinderSupportTests.java b/spring-cloud-stream-binders/spring-cloud-stream-binder-test/src/test/java/org/springframework/cloud/stream/binder/MessageChannelBinderSupportTests.java
index 183a4e3db..584b422c8 100644
--- a/spring-cloud-stream-binders/spring-cloud-stream-binder-test/src/test/java/org/springframework/cloud/stream/binder/MessageChannelBinderSupportTests.java
+++ b/spring-cloud-stream-binders/spring-cloud-stream-binder-test/src/test/java/org/springframework/cloud/stream/binder/MessageChannelBinderSupportTests.java
@@ -119,22 +119,20 @@ public class MessageChannelBinderSupportTests {
 	}
 
 	@Test
-	public void testContentTypePreserved() throws IOException {
+	public void testContentTypePreservedForJson() throws IOException {
 		Message<String> inbound = MessageBuilder.withPayload("{\"foo\":\"foo\"}")
 				.copyHeaders(Collections.singletonMap(MessageHeaders.CONTENT_TYPE, MimeTypeUtils.APPLICATION_JSON))
 				.build();
-		MessageValues convertedValues = binder.serializePayloadIfNecessary(
-				inbound);
-
+		MessageValues convertedValues = binder.serializePayloadIfNecessary(inbound);
 		Message<?> converted = convertedValues.toMessage();
-
-		assertThat(contentTypeResolver.resolve(converted.getHeaders())).isEqualTo(MimeTypeUtils.TEXT_PLAIN);
-		assertThat(converted.getHeaders().get(BinderHeaders.BINDER_ORIGINAL_CONTENT_TYPE)).isEqualTo(MimeTypeUtils.APPLICATION_JSON.toString());
+		assertThat(contentTypeResolver.resolve(converted.getHeaders())).isEqualTo(MimeTypeUtils.APPLICATION_JSON);
+		assertThat(converted.getHeaders().get(BinderHeaders.BINDER_ORIGINAL_CONTENT_TYPE)).isNull();
 		MessageValues reconstructed = binder.deserializePayloadIfNecessary(converted);
 		assertThat(reconstructed.getPayload()).isEqualTo("{\"foo\":\"foo\"}");
 		assertThat(reconstructed.get(MessageHeaders.CONTENT_TYPE)).isEqualTo(MimeTypeUtils.APPLICATION_JSON_VALUE);
 	}
 
+
 	@Test
 	public void testContentTypePreservedForNonSCStApp() {
 		Message<String> inbound = MessageBuilder.withPayload("{\"foo\":\"bar\"}")
@@ -180,35 +178,35 @@ public class MessageChannelBinderSupportTests {
 
 	@Test
 	public void mimeTypeIsSimpleObject() throws ClassNotFoundException {
-		MimeType mt = JavaClassMimeTypeConversion.mimeTypeFromObject(new Object());
+		MimeType mt = JavaClassMimeTypeConversion.mimeTypeFromObject(new Object(), null);
 		String className = JavaClassMimeTypeConversion.classNameFromMimeType(mt);
 		assertThat(Class.forName(className)).isEqualTo(Object.class);
 	}
 
 	@Test
 	public void mimeTypeIsObjectArray() throws ClassNotFoundException {
-		MimeType mt = JavaClassMimeTypeConversion.mimeTypeFromObject(new String[0]);
+		MimeType mt = JavaClassMimeTypeConversion.mimeTypeFromObject(new String[0], null);
 		String className = JavaClassMimeTypeConversion.classNameFromMimeType(mt);
 		assertThat(Class.forName(className)).isEqualTo(String[].class);
 	}
 
 	@Test
 	public void mimeTypeIsMultiDimensionalObjectArray() throws ClassNotFoundException {
-		MimeType mt = JavaClassMimeTypeConversion.mimeTypeFromObject(new String[0][0][0]);
+		MimeType mt = JavaClassMimeTypeConversion.mimeTypeFromObject(new String[0][0][0], null);
 		String className = JavaClassMimeTypeConversion.classNameFromMimeType(mt);
 		assertThat(Class.forName(className)).isEqualTo(String[][][].class);
 	}
 
 	@Test
 	public void mimeTypeIsPrimitiveArray() throws ClassNotFoundException {
-		MimeType mt = JavaClassMimeTypeConversion.mimeTypeFromObject(new int[0]);
+		MimeType mt = JavaClassMimeTypeConversion.mimeTypeFromObject(new int[0], null);
 		String className = JavaClassMimeTypeConversion.classNameFromMimeType(mt);
 		assertThat(Class.forName(className)).isEqualTo(int[].class);
 	}
 
 	@Test
 	public void mimeTypeIsMultiDimensionalPrimitiveArray() throws ClassNotFoundException {
-		MimeType mt = JavaClassMimeTypeConversion.mimeTypeFromObject(new int[0][0][0]);
+		MimeType mt = JavaClassMimeTypeConversion.mimeTypeFromObject(new int[0][0][0], null);
 		String className = JavaClassMimeTypeConversion.classNameFromMimeType(mt);
 		assertThat(Class.forName(className)).isEqualTo(int[][][].class);
 	}
diff --git a/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/binder/AbstractBinder.java b/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/binder/AbstractBinder.java
index b1752b18b..66645644a 100644
--- a/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/binder/AbstractBinder.java
+++ b/spring-cloud-stream/src/main/java/org/springframework/cloud/stream/binder/AbstractBinder.java
@@ -46,6 +46,7 @@ import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.MimeType;
 import org.springframework.util.MimeTypeUtils;
+import org.springframework.util.ObjectUtils;
 import org.springframework.util.StringUtils;
 
 /**
@@ -200,12 +201,13 @@ public abstract class AbstractBinder<T, C extends ConsumerProperties, P extends
 		Object originalContentType = message.getHeaders().get(MessageHeaders.CONTENT_TYPE);
 
 		//Pass content type as String since some transport adapters will exclude CONTENT_TYPE Header otherwise
-		Object contentType = JavaClassMimeTypeConversion.mimeTypeFromObject(originalPayload).toString();
+		Object contentType = JavaClassMimeTypeConversion
+				.mimeTypeFromObject(originalPayload, ObjectUtils.nullSafeToString(originalContentType)).toString();
 		Object payload = serializePayloadIfNecessary(originalPayload);
 		MessageValues messageValues = new MessageValues(message);
 		messageValues.setPayload(payload);
 		messageValues.put(MessageHeaders.CONTENT_TYPE, contentType);
-		if (originalContentType != null) {
+		if (originalContentType != null && !originalContentType.toString().equals(contentType.toString())) {
 			messageValues.put(BinderHeaders.BINDER_ORIGINAL_CONTENT_TYPE, originalContentType.toString());
 		}
 		return messageValues;
@@ -339,13 +341,14 @@ public abstract class AbstractBinder<T, C extends ConsumerProperties, P extends
 
 		private static ConcurrentMap<String, MimeType> mimeTypesCache = new ConcurrentHashMap<>();
 
-		static MimeType mimeTypeFromObject(Object payload) {
+		static MimeType mimeTypeFromObject(Object payload, String originalContentType) {
 			Assert.notNull(payload, "payload object cannot be null.");
 			if (payload instanceof byte[]) {
 				return MimeTypeUtils.APPLICATION_OCTET_STREAM;
 			}
 			if (payload instanceof String) {
-				return MimeTypeUtils.TEXT_PLAIN;
+				return MimeTypeUtils.APPLICATION_JSON_VALUE.equals(originalContentType) ? MimeTypeUtils.APPLICATION_JSON
+						: MimeTypeUtils.TEXT_PLAIN;
 			}
 			String className = payload.getClass().getName();
 			MimeType mimeType = mimeTypesCache.get(className);